86 INSECTA. 
‘ 
Cimpex, Oliv. Fab.—Crabro, Geoff. 
The larve have but twenty-two feet. Some of them when irritated 
spurt a greenish liquor from the sides of their body to the distance 
of a foot. 
Dr Leach(1), by having recourse to the number of joints anterior 
to the club, their relative proportions and the arrangement of the 
cells of the wings, has divided the genus Cimbex into several others, 
one of which, Perca(2), is peculiar to New Holland, and is distin- 
guished from all the others by the following characters. The four 
posterior tibia have a movable spine on the middle of their inferior 
side. The scutellum is large and square, with its posterior angles 
projecting in the form of teeth. The valves that sheathe the ovi- 
positor are covered externally with numerous short and frizzled 
hairs. The antenne are very short and have six joints, the last of 
which, or the club, is without any vestiges of annuli as in SyzyGonta, 
a genus established by Kliig on some species from Brazil(3). The 
radial cell is appendiculated, and there are four cubital cells, the 
second and third of which receive, each, a recurrent nervure—the 
transverse nervures of the disk. 
M. Lepeletier de St Fargeau, in an excellent Monograph of the 
Tenthredinetz, only adopts the genus Perga, and in conjunction with 
him we will consider those of the English naturalist as simple divi- 
sions of Cimbex. 
The two following species belong to that number in which the 
-antenne have five joints before the club. 
C. lutea; Tenthredo lutea, L.; De Geer, Insect., I], xxxiii, s— 
16. About an inch in length; brown; antennz yellow; abdomen 
yellow, with violet-black bands. 
The larva, or pseudo-caterpillar, is of a deep yellow, with a 
blue stripe, edged with black along the back. On the Willow, 
Birch, &c. : 
(1) Zool. Miscel., IIT, p. 100, et seq. 
(2) Ibid., 116, cxlviii; Lepel., Monog. Tenthred., p. 40. 
(S$) Monog. Entom., p. 177; in the same work, p. 171, he gives the characters 
of another genus Pachylosticta, also peculiar to Brazil. The antenne consist of 
five joints. The superior wings are dilated near their extremity, and the callous 
point is semilunar. The second, third and fourth joints of the posterior tarsi 
are very short. He mentions three species. 
The genus Perga, on account of the cells of the wings and the spines of the 
posterior tibia, should come directly before Hylotoma. 
