50 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 96 the rudiment of the virga, and evidently cannot represent the median

ventral phallomere of Blatta or Periplaneta because of its position dorsal tothe genital opening.

The

external genitalia of Ectobius lapponicus have the

same

type of structure as those ofBlattella,butin

most

respectsthey are simpler.

The

exposed part of the ninth abdominal

sternum

of the adult male

Fig. 17.

—

Blattoidea: abdomen and external male genitalia of Blattella ger- manica (Linnaeus).

A, adult male, end of abdomen, ventral view. B, same, vi^ith left phallomere projected. C, same, proctiger and basal hooks (a, b) beneath tenth tergum, ventralview. D, nymph3

mm

long,abdomen,ventral surface. E,

nymph

22

mm

long,end of abdomen, ventralview. F, same, phalliclobes removed from geni- tal chamber, dorsal view. G,left phallomere of followingnymphal instartaken from withincuticula ofleftlobe of F. H,leftphallomereof adult.

For letter explanation, see preceding figures.

forms an

asymmetrically triangular subgenital plate (fig. i8A, B,

IXS)

projecting far

beyond

the short

tergum

of the tenth

segment

(A,

XT), and

bearingthe coalesced rudiments of the styli (B, Sty) atits apex.

The

anterior invaginated part of the ninth

sternum (E)

is produced into

two

long

apodemal arms (IXSAps)

extending far

forward

in the

abdomen,

the left

arm

being longer than the right.

Above

the external part of the ninth sternum is thegenital chamber,

NO. 5

MALE GENITALIA

OF ORTHOI'TEROID INSECTS

SNODGRASS

Si within

which may

be seen the short

membranous

penis (A, E,

Pen),

but the phallomeres arc usually entirely concealed in their lateral pouches (E,3;,c).

The much-reduced

rightphallomere (D, E,

rPhm)

consists of

two

small sujjerposed lamellae at the bottom of the right

pouch

_(y), with a short

apodeme

(/>) projecting

from

the wall of the latter.

The

left phallomere is a long, thick, strongly sclerotized rod with a

hooked

extremity (E, IPhni), contained in a corres- pondingly deep

pouch

{s).

By

the complete eversion of the pouch, however, theleft phallomere can be protracted far

beyond

the end of

IPhm

Fig. 18.

—

^Blattoidea: abdomen and external male genitalia of Ecfobius lap- ponicus (Linnaeus).

A, end of abdomen, showing penis (Pen) in base of genital chamber, dorsal view. B, same, ventral view. C, same, ventral view, with left phallomere pro- jected on everted pouch (^). D, right phallomere in right phallic pouch _(y).

E, general view of retracted genitalia, somewhat diagrammatic, including ninth sternum and its apodemal arms (IXSAps), dorsal view. F, left phallomere projected, penis (Pen), and endophallicapodeme (Ape).

For letter explanation, see fig. 16.

the

abdomen

(C, F).

The

penis is a short

membranous

lobe (E, F,

Pen)

with a small endophallic cavity opening at its extremity.

The

penis is

unarmed,

but

from

the endophallic wall there arises a long

apodeme (Ape), which

extends

forward and

totheleft intothe fourth abdominal segment.

The

type of phallic structure here

shown

in Ectobia

and

Blattella, representing the Ectobiinae

and Pseudomopinae,

_occurs in

many

otherforms,certainly including, asisevident

from

the descriptions

and

figures of

Chopard

_(1920), the Nyctiborinae, Epilamprinae,

Pan-

chlorinae,

and

Perisphaerinae.

52

SMITHSONIAN MISCELLANEOUS COLLECTIONS

VOL.

96 The

female genitalia.

— The

external genital structures of female Blattidae include the opening of the

median

oviduct, the aperture of the spermatheca, the ovipositor, the opening of the accessory glands,

and

the oothecal

mold

; they involve the seventh abdominal sternum

and

the ventral parts of at leastthe eighth

and

ninth abdominal seg- ments.

The

genitalia arecompletely concealed in alarge cavity above the seventh sternum,

which

latter is prolonged beneath the ventral parts of the succeeding segments.

The

short ovipositorarises (inthe adult)

from

the venter of the ninth

segment

in the dorsal wall of the cavity.

The

small anterior part of the cavity lying before the ovi- positor

and

above a fold representing the eighth

sternum

corresponds withthe usual genital

chamber

of the eighth

segment

(see Snodgrass, 1933,^fig.23) ^;the

much

largerposteriorpart,orvestibule, lyingabove the seventh

sternum

contains the ovipositor anteriorly,

and forms

distally a

mold and

container for the ootheca.

The

opening of the oviduct (gonopore) lies

on

a fold or lobe of the venter of the eighth segment,thespermatheca opens

somewhere

between the

gonopore and

the ovipositor,

and

the accessory glands discharge behind the base of theovipositor.

The

spermathecaof Blattidaeisa two-branchedstructure (figs. 1 1 I,

15F), one branch,

which

^is usually thickerthan the other or enlarged at the end, being the true

sperm

receptacle, the other apparently a glandular accessory. In Blatta

and

Pcriplancta there is but one spermatheca; in Blattella there are

two

complete spermathecae (fig,

19 B), each with ^{a separate} opening

and

a glandular branch.

Ac-

cording to Cleveland (1934)

two

spermathecae are present also in Cryptocercus punctidatns.

The

larger branch of the spermatheca of Blattaorientalis (fig. ill, Spt) is traversed by a

narrow

axial canal with strongly sclerotic walls,

from which

are given off

numerous

fine canaliculi into the cells of the thick glandular epithelium. In a preliminary study ^{the writer} mistook these threadlike ductules for spermatozoa,

and made

the foolish statement that the supposed sper-

matozoa

^{are attached to a} long spermatophore (Snodgrass, 1936, p. 90). Ito (1924), however, has

shown

the true nature of the struc- tures radiating

from

the central canal.

He

says, moreover, that the

lumen

of the spermatheca, after copulation, is filled with spermatozoa

and

finegranulesofsecretion.

The

spermathecaof Blatta

and

of Peri- planeta opens

upon

a small papilla on a

median

sclerite in the dorsal wall of thegenital

chamber

(figs. 11 F, G, 15 G,

Spr)

proximalto the base of the ovipositor. In Blattella the spermathecae have quite a different position, as will be

shown

later, and their openings have a veryspecial relation to thegonopore.

NO. 5

MALE GENITALIA

OF

ORTHOPTEROID

INSECTS

SNODGRASS

53