64 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 96 generally produced in a pair of soft lateral folds or rounded lobes (h),

and

associated with these structuresis usually a pair of scleroticbars or plates (i), the ends of

which may

project as free processes.

The

anatomicalrelations of the various parts of the phallusin theordinary retracted state are best seen in a

median

longitudinal section

(D), from which

it

becomes

evident that the entire organ is merely an outgrowth

from

the genital

chamber

wall (x-x), enclosing a large endophallic cavity

{Enph),

into

which

opens the ejaculatory duct {Dcj). Disregarding the modification of the dorsal lobe, therefore,

Fig. 23.

—

TeUigonioidea-Tettigoniidae^: external malegenitalia of Conocepha- his fasciatus (Degeer).

A, nymph, 9

mm

long, end of abdomen, ventral view. B, C, same, phallus in dorsal and ventro-posterior views. D, nymph, 11

mm

^{long, end of abdomen.}

E, F, same, phallus in posterior and ventral views. G, nymph, 14

mm

long, phallus, dorsal view. H, adult, phallus, posterior view.

For letter explanation, see fig. 22.

the essential structure of the phallus

may

be expressed as in the

diagram

atA,orinsectionas atB. Thissimplifiedconceptof the adult phallic structure is the actual structure of the organ in late

nymphal

stages of its development (fig. 23 E, G).

The

male organs of the Tettigoniidae have been well described

by Walker

(1922),

though

in terms

somewhat

different

from

those used here because based on a different ideaconcerning the origin

and

evo- lutionof the phallus.

The

paired processes or armature of the dorsal phallic lobe

Walker

calls the ^"parameres ^", the dorsal cavity the

"

paramere

sac ^",

and

the endophallic cavity the "spermatophore sac."

NO. 5

MALE GENITALIA

OF

ORTHOPTEROID

INSECTS

SNODGRASS

65

The

so-called parameres of the Tettigoniidae are supposed to repre- sent the paired right

and

left phallic lobes of Blattidae, but, as will presentlybe shown,the developmentof thetettigoniid phallusdoesnot warranttheassumption of aclose

homology between

any of its

minor

parts

and

the phallic structuresof Blattidae.

Though

the tettigoniid phallus is ordinarily concealed within the genital chamber, the entire organ is protractile. In the protracted condition (fig. 22

E)

the dorsal cavity with its armature is everted,

and

all parts of the phallus

may

be so greatly distended

by

blood pressure that theorgan

assumes

an entirelydifferent appearance

from

that of its passive state.

The

principal muscles of the phallus are a pair of dorsal retractors (fig. 24^B, rpd) arising

on

the lateral parts of the tenth abdominal tergum,

and

apair of ventral retractors {rpv) arising on the ninth sternum.

The

development of thetettigoniidphallus in

nymphal

instars

shows

that the adult organ is a composite structure

formed by

the union of several

primary

lobesof the genital integumentthat

grow

out

around

the gonopore, or

mouth

of the invagination that gives rise to the ectodermal part of the ejaculatory duct. In a

young nymph

of

Cono-

cephalus fasciatus,

9 mm

^{in length (fig.} 23

A),

the

gonopore

is sur-

rounded by

six small phallic lobes (B, C),

two

of

which

are dorsal,

two

lateral,

and two

ventral.

These

simple lobes, or phallomeres, enclose

between them

a shallow endophallic cavity, to the base of

which

isattached the ejaculatoryduct.

The

early

nymphal

phallomeres of Conoccphalus thus resemble the

nymphal

phallomeres of Blatta or Pcriplaneta (figs. 12E, 15 C), except that there are six of

them

instead of three.

At

this stage, therefore, it is impossible to identify

any

particular pair of lobes in Conocephahis with

any

particular pair inBlatta or Pcriplaneta.

At

alater stage inthe development of

Cono-

cephahis, in a

nymph

11

mm

long (fig. 23

D),

the

two

primary dorsal phallomeres have unitedin asinglebroad dorsal lobe (E, dl),

and

the

two

ventral phallomeres have united in a single ventral lobe (E, F, vl), the lateral lobes {II) retaining their independence. All the lobes, moreover, are

now

carried out

on

a

common

basal ring,

and

the endo- phallic cavity is correspondingly deepened.

Thus

is established the typical four-lobed structure of the adult phallus, but the special features of the dorsal lobe are not yet in evidence.

At

a still later stage, in a

nymph

14

mm

ⁱⁿ length, the basal part of the phallus has greatly lengthened (G), so that the

primary

phallomeres

now

appear as relatively small terminal lobes, with the

wide

phallotreme between them.

The

dorsal lobe (dl) still presents a broad flat upper surface, but there are dififerentiated

upon

^it

two

oval thickenings {h),

which

66 SMITHSONIAN MISCELLANEOUS COLLECTIONS

VOL.

96

evidently are the rudimentsof the adultarmature

(H,

h, i).

The ma-

ture structure of the phallus

(H)

apparently ^is attained at the last

moult; it involves principally the thickening of the dorsal lobe, the invagination of the upper surface of the latter,

and

the development of the dorsal armature characteristic of the species.

The

adult modifications of thetettigoniidphallus consist principally of variations in the relative size of the several terminal lobes,

and

in the

form and

development of the armature of the dorsal lobe. In the Decticinae, however, the cavity of the dorsal lobe

becomes

con- verted into apocket

by

the posterior extensionof its anterior margin,

which

condition leads into thatcharacteristic of the

Rhaphidophorinae

(fig. 22 F),

and

finally to an

extreme

type of modification that dis- tinguishes the Gryllidae

from

the Tettigoniidae,

Fig. 24.

—

Tettigonioidea-Tettigoniidae: external male genitalia of Micro- centrum retinerz'e (Burnieister).

A, endofabdomen, lateral view. B, phallus, posterior \iew. C, same, median longitudinal section.

For letter explanation, see fig. 22.

For

a concrete

example

of a phallic structure that

comes

close to the hypothetical generalized structure

shown

at

C

^{of figure 22}

^we may

select the genus

Microcentrum. The

phallus of

M.

retinerve (fig.

24 B)

isa low,

rounded organ

witha basinlike cavity (dc) ⁱⁿthe dorsal wall, a pair of folded lateral lobes _(//),

and

a thick, bifurcate ventral lobe (vl).

The

phallotreme (Phtr) is a wide, transverseopen- ing

between

thedistal lip (g) of the dorsal lobe above,

and

the lateral

and

ventral lobes below.

The

dorsal cavity contains

two

large, oval, strongly

convex

protuberances (h), transversely ribbed

on

their lateral surfaceswith ^finelytoothed ridges, butthereis

no

other acces- soryarmature. Attached

on

the inner surfaces of these dorsal organs are large masses of muscle fibers converging

from

^{the lateral parts} of the base of the phallus.

The

dorsal

and

ventral retractor muscles (rpd, rpv) have the typical

arrangement and

are inserted on the phallic base.

A median

section of the organ

(C) shows

clearly the

NO. 5

MALE GENITALIA

OF

ORTHOPTEROID

INSECTS

— SNODGRASS

67 simple anatomical relations of its parts, includins^- the endophallic cavity

(Enph)

thatreceivesthe ejaculatoryduct (Dej). Intheclosely related

M.

rhonihifolium the phallus has the

same

general structure as that of retinerve, but the organs of the dorsal cavity are absent.

A nymphal

condition of the phallus appears to be retained in the adult of

Amhlycorypha

oblongifoUa, since the phallic organis here a small, soft,

compact body

presenting abroad,flat dorsalsurface with- out the usual dorsal cavity

and

armature.

The

endophallic cavity, however, contains a flat, tonguelike fold that divides it into a dorsal

Fig. 25.

—

Tettigonioidea-Tettigoniidae: abdomen and genitalia of male of Phancroptera jurcata (Brunner).

A, end of abdomen, lateral view. B, tenth tergum and cerci, dorsal view.

C, tenth and eleventh abdominal segments, ventral view. D, phallus, posterior view. E, same, dorsal view. F, same, median longitudinal section. G, phallus and associated internal organs, ventral view.

For letter explanation, see fig. 22.

and

a ventralcompartment.

The

foldarisesbya

narrowed

baseabove thegonopore,

and

ends with

two

small divergent lobes projecting

from

the phallotreine.

Inthegenus Phancropterathe male^"terminalia ^"include

numerous

modifications of the ninth, tenth,

and

eleventh abdominal segments.

In^. fiircata (fig. 25

A)

the

tergum

of the ninth

segment

resembles thetergal platesprecedingit,but the ninth

sternum (IXS)

^isproduced posteriorly in a long, slender, tapering, trough-shaped extension, strongly curved

upward,

ending in a

narrow

truncate margin. Styli are absent unless they are represented

by two

small nodules

on

the