INSECTS. 
343 
C ‘UP. X. 
these organs for burrowing in sand-banks and making 
their nests. . 
The tarsi of the front-legs are dilated m many male 
beetles or are furnished with broad cushions of hairs; 
and in’ many genera of water-beetles they are armed 
With a round flat sucker, so that the male may adhere 
to the slippery body of the female. It is a much more 
Unusual circumstance that the females of some water- 
beetles (Dytiseus) have their 
olytra deeply grooved, and 
in Acilius sulcatus thickly set 
with hairs, as an aid to the 
male. The females of some 
other water-beetles (Hydro- 
porus) have their elytra 
Punctured for the same ob- 
ject. 8 In the male of Cnibro 
c rtbrarius (fig. 8.), it is the 
tibia which is dilated into a 
broad horny plate, with mi- 
Unte membraneous dots, giv- 
iiig to it a singular appear- 
ance like that of a riddle.' 
In the male of Penthe (a 
genus ot beetles) a lew 0I ' maUs . ^figure, female, 
fbe middle joints of the an- 
teimar are dilated and furnished on the inferior surface 
8 We have here a euiiona ana Inexplicable ease of dimorphism, for 
s «m e of the females of four European species of Dytiseus, and of certain 
species of Hydroporus, have their elytra smooth; and no intermediate 
gradations between sulcated or punctured and quite smooth elytra 
We been observed. See Dr. H. Schaiun, as quoted in the Zoologist, 
Vol. y.-vi. 1847-18, p. 1896. Also Kirby o.u<l Spence, ‘Introduction to 
Eutomology/ vol. iii. 1826, p. 305. . m1 „ 
7 Westwood, * Modern Class/ vol. ii. p. 193. The following state- 
ment about rent lie, and others in inverted commas, are taken from 
Walsh, ‘Practical Entomologist, Philadelphia, vol, ii. p. 8S, 
