The genus is much modified, but apart from its peculiarities it shows the subfamily characteristics of the Chilosinae. A rather poor representation of material permits the use of certain characters which would probably have to be abandoned if a key were made for both North and South America, or even if a greater representation of the South American material were available. C\ Squamae, squamal cilia and plumula well developed, cilia of the lower squama equal to at least half the length of the halter; flies usually of broad form.
AKT.9 FLIES OF THE FAMILY SYRPHIDAE SHANNOX 3 D\ Second abdominal segment strongly contracted and several times longer than wide, or abdomen very long and slender throughout. 9 FLIES OF THE FAMILY SYKPHIDAE SHANNON 9 Head hemispherical, circular in outline (front view), face projecting beyond antennal prominence; front unusually narrow; ocelli far advanced from occipital margin; eye almost bordering mouth rim; posterior oral region yellow; dorsum of thorax bordered by a yellow border; metapleura yellow; abdomen basally contracted;. Belongs to the genus Baccha, but can be easily separated by the unusually elongated and slender abdomen of the female, which is cylindrical and almost twice the length of the wing and.
The last segment, however, must be part of the usually retracted and very small first joint of the egg. Female.—The similar Bacchi {Pelecinobaccha) peruvianain has an elongated abdomen nearly twice as long as the length of the wing (9:5), but the fifth and sixth segments, though well developed, are much shorter. JiBT.9 FLIES OF THE FAMILY SYEPHIDAE SHANNON" 11 than the preceding segments and wider, giving the abdomen a subscapular shape.
9 FLIES OF THE FAMILY SYRPHIDAE SHANNON 13on the sides of the second tergite, on the sides and through the middle of the third.
ART. 9 FLIES OF THE FAMILY SYRPHIDAE SHANNON 13 on sides of second tergite, on sides and through the middle of third
Most of these species are very closely related, and in order to work out a synoptic key for them it is necessary to have specimens at hand.
ART. 9 FLIES OF THE FAMILY SYRPHIDAE SHANNON 15
In the genotype the brown borders on the fifth vein behind to the base of the last posterior cell, and extends thence to the posterior corner of the first. Frons black pilose, rather broad, opaque brown, lower part shiny black; antennae dark brown; face broad, concave between antennae and facial tubercle moderate; sides of face with long, sparse pile; anterior half of mesonotum with black and yellow piles intermixed, posterior half and scutellum black pilose, a few yellow hairs on posterior margin of scutellum; legs dark brown, tarsi paler;.
It can be easily recognized by the rather short yellowish pole and a few pale transverse spots on the second tergite. Head fairly broad and flat; eyes bare; front lined with yellow and black pile: antenna normal, brownish; arista yellowish; face glossy black, deeply concave, tubercle prominent; facial bone produced downwards, the sides with pale pollen and pile; .. thorax with black and yellow pile mixed, with the yellow predominating; base of femora yellow, brownish outside; top of hind thigh yellow; hind thigh moderately swollen with spines and black bristly hairs underneath; tibiae yellowish brown, tarsi l)tanned;. The JSlicrodontinae of the American tropics appear to have an almost unlimited variation in shape and color and this, combined with the large number of species found in this region, makes the group very confusing.
A small group (about ten species) possess a type of habitus that is so similar in appearance to the stingless bees (THgona) of the Americatropics that they can easily be confused with them at first glance. Walker' erected the genus Uhristes for one of the species ^Y which he described as flavitihia, and it is here proposed to use this name in the subgeneric sense for this group of species. A group notable for its similarity in appearance to the stingless honey bees of the genus Tngona.
Walker described only one species, favifihia, although the other species recorded here (from the British Museum) were apparently before him at the time. Four visible segments, of which the fourth is clearly longer than the third; wings uniformly drenched trigoniformis, new species. 31ale.– A rather small, blackish species, with eyes fairly close together above the antennae; ocelli closely grouped and centrally located on the upper part of the anterior (=ocellar) triangle; the first antennal joint is about twice as long as it is wide, the second is equal to half the length of the first, and the third is twice as long as the first; face black, narrowly yellowish on the sides next to the eye-rim; face narrow,.
He.—Similarto Iacteipe7i7iis,but the first antennal joint is equal to the third; the wings are uniformly infuscate; hind tibia very much. Front slightly wider than long, upper three-quarters inflated; antennae yellowish brown, slightly longer than fore tibiae, first joint nearly three times as long as wide, the second ca. one-fourth of the first joint, the third slightly longer than the combined length of the second; Arista as long as first; the face is almost parallel, approx. twice as long as wide; fore and middle legs yellowish, hind legs darker, hind legs as in trigoniformis] abdomen with sides behind second tergite, but slightly turned below (probably distinct in male). She. – Differs considerably from the other species of this subgenus in having the abdomen broadly ovoid and the scutellum produced in the form of a triangular shape.
Head black, front and face extremely narrow, front nearly three times longer than broad, ocular region elongate; antennal nodes 1:0.25:1; arista shorter than third node; face narrowed below, pale pale, sides pollinated white; thorax dark brown, dark pilose; all legs dark brown, apical tarsal joints yellow; hind femur and tibia rather thin, long dark, dorsal cut of tibia wide and rather shallow; hind metatarsus much larger in circumference than femur or tibia; belly brown, sides narrowly yellow, second and third with a pair of large yellow spots; fifth tergite developed, yellow, with a median, longitudinal, dark stripe; wings large, slightly infuscate, with a median, rather pale, white cross-stripe. Male.—This species can be easily recognized by the presence of a well-developed tooth-like process at the base of each basitarsus. Ej^e edges parallel, front and face less than one-third width of head; anterior part dark, ocular region elongate.
AET. 9 FLIES OF THE FAMILY SYEPHIDAE SHANNON 21
1:0.25:1; base of first joint yellowish; face slightly wider, more prominent downwards; thorax darker, humerus yellowish; shield with a purplish reflection and without spines; hind thigh with relatively few black spines underneath; abdomen club-shaped, second segment.
NOTES AND DESCRIPTIONS OF SPECIES FROM CHILE The Diptera of Chile were given considerable attention from 1834
AHT. 9 FLIES OF THE FAMILY SYRPHIDAE — SHANNON 23 Very little has been written on the Chilean Diptera since that time
9 FLIES OF THE FAMILY SYRPHIDAE — SHANNON 23 Very little has been written since that time on the Chilean Diptera. Name preoccupied by Syrphus interruptus Gmelin, 1792). The usual transverse yellow bands are reduced to a few submedian yellow spots on each segment which may be connected by slender connections with the yellow laterals. The species available are apparently more closely related to the genotype of Allograpta, obliqua Say, than to the genotypes of the other two generations and are therefore considered here under Allograpta.
AKT. I) FLIES OF THE FAMILY SYRPHIDAE SHANNON 25
Faz, were determined as Syrphus decermnaeulata Rondani (Aldrich); two with puparia mounted on the same pegs and labeled South Chile, at Lohello. This should be especially true since the next species is a very close ally of the current one.
ART. 9 FLIES OP THE FAMILY SYRPHIDAE — SHANNON 27
It seems quite certain that one of them is the same species as that described by Macquart under the name Syrphus rrielanostoina. A}!T.9 FLIES OF THE FAMILY SYRPHIDAE SHANNON 29with a pair of yellow moons that do not protrude to the sides of the with a pair of yellow moons that do not protrude to the sides of the abdomen; posterior margins of fourth and fifth tergites yellow, the fifth with a few small yellowish spots on the anterior margin; Wings. Female. Closely related to inelanostomy, but differs in that the front and face are narrower; face pile entirely pale; shield completely yellowish; hind femur less extensively black, almost half of the apical half yellowish; tarsi yellower; the yellow belly spots are clearly larger and less curved, with the black separating the spots in each pair being narrower than the length of the spots (from front to back) (in melanostoma the black separating the spots is much wider than the length of the spots).
This species can hardly be described as Macquart's melanostom^a, as the yellow abdominal spots are considerably larger and more rounded than in pirastri. A species easily recognized by the brown front and face, bordered by a narrow yellow border; truncate yellow lines on anterior corners of mesonotum; scutellum yellow and wings hyaline with a brown spot in the middle of the anterior margin. Male.—Agrees with Philippi's description of valdiviana, except that this species is said to have the hyaline wing with three points, whereas the present species has the wings entirely smoky and without spots.
The vestigial alula as well as the basal part of the axillary cell connect this species to the flagellum.
ART. 9 FLIES OF THE FAMILY SYRPHIDAE SHANNON 31
A species easily recognized by its reddish yellow legs; sides of mesonotum with a distinct gray pollinose border; strongly contracted abdomen; metasternum completely girdled with chitin and a rather small dark spot at the base of the subcostal cell. Named after the famous naturalist, Charles Darwin, who collected the species while on the famous voyage of the Beagle. 9 FLIES OF THE FAMILY SYRPHIDAE SHANNON 33 Antennae black, the third joint small and tearistalless stout (nor- Antennae black, the third joint small and tearistalless stout (nor- . mal type) as in nigra.
The face is rather deeply concave, with the epistoma projecting slightly next to the antennal prominence; legs browner than in nigra, the trunk more yellowish; abdominal muscle.
