164 
ending each side in an oval wrinkled area. The second and third glands, 
closely resembling each other, follow on the next two segments, and there 
is a similar transverse slit, more distinct however, ending each side in a 
hook-shaped groove with raised inner margin. ‘There is often a trace of a 
fourth gland on the suture between the sixth and seventh segments. 
There are at least three mediodorasl plates, one for each gland, often a 
small fourth one, and sometimes more, as in Cydnidae. The plates are 
sometimes divided medially or are partly confluent (Corimelaena). 
Behind each abdominal spiracle except the first are usually a pair of 
large setigerous punctures, the spiracular punctures, which are longitu- 
dinally placed in the Thyreocorinae, and included with the spiracle in the 
lateral plate. In the other subfamilies studied they are outside the lateral 
plate, placed transversely, except that in Cydnini they become oblique on 
segments 3-6 from the shifting of the inner one, and in Perillus from the 
crowding of the outer one by the lateral plate. 
The genital structures are scarcely differentiated enough in the 
nymphs for use in classification. The male may be distinguished by the 
swollen penultimate Ventral, which is often longer at middle than near 
the ends; sometimes there is a triangular depression on the hind margin 
at middle, notching the swollen portion. In the female this segment is 
not swollen, nor longer on the median line, and the entire median part is 
usually separated off to form a small depressed and flattened plate. 
In the first and second instars the mesonotum is of nearly equal 
width throughout; the metanotum is similar, reaching the ‘lateral margin 
and more or less convexly curved behind. In the third instar the meta- 
notum is still curved behind and ‘laterally tapers to a point near the 
margin; in the fourth it is nearly straight behind or, in Scutellerinae, a 
little convex at middle, and is overlapped now at each end by the anterior 
wing-pads, which attain its hind margin. In the fifth and last instar 
both wing pads project backwards well beyond the middle part of the 
metanotum, and the scutellum usually attains its hind margin at middle 
in Pentatomidae, but hardly in Cydnidae.. The characterizations in the 
nymphal keys apply especially to the last instar, but are constructed so 
that they will usually answer for the fourth, and often for the third also. 
Superfamily PENTATOMOIDEA 
The group covered in this paper is the superfamily Pentatomoidea 
of Uhler’s check-list and Kirkaldy’s Catalogue, and the family Pentatom- 
idae of Lethierry and Severin’s Catalogue and of Van Duzee’s Anno- 
tated List and his Catalogue. It is a well-marked group, recognized by 
the five-segmented antennae, the broad form, and the size of the scutel- 
lum, which is always at least moderately large, and often greatly expanded 
so as to cover nearly the entire dorsum behind the pronotum, as well as 
all of the elytra except the costal border. The present group includes 
three families. One of them, Urolabididae, is confined to Asia, Australia, 
and neighboring islands. The other two may be separated as follows. 
