7524 Insects. 



the aid of a lens, the opening or mouth of a duct closed by a valve, 

 whence the larva, on being touched, discharges a colourless fluid, 

 which 1 could not pei'ceive to have any particular odour. This dis- 

 charge of a fluid serves probably to defend the animal from the attacks 

 of female ichneumons, so that 1 was surprised to observe that the larva 

 did not emit the fluid every time it was touched, but allowed some 

 time to elapse, as if it had first to awake from a half sleep. 



The full-grown Cimbex larva is a handsome insect. When young 

 it is gray, powdered as it were with white, having two yellow spots on 

 each dorsal segment in place of the orange stripes ; there are then 

 four spots on the sides and one in the centre of the back. The length 

 of the full-giown larva is 16 lines. 



During the day they remain at rest on the branches or among the 

 leaves, but on the approach of evening twilight they crawl higher up 

 and begin to feed, gnawing the leaves from the edge towards the mid- 

 rib. They are full-grown in the first days of July, and begin to spin 

 up between the twigs and among the fallen leaves. The cocoons are 

 hard, and made of a brown silky material. The latest larvae which I 

 observed to spin up made yellow cocoons. 



On the 1st of April, 1845, I opened two yellow cocoons, and found 

 pupge (fig. 4) inside. The anterior part of the body was brownish 

 yellow, and the abdomen green, with a rather broad brownish stripe 

 over the back ; the compound eyes brown, and visible through the 

 outer skin ; between the eyes hung the while antennae, which are 

 easily seen to be six-jointed ; attached to and beneath the head the 

 jaws and palpi were readily distinguished ; the six legs lay with the 

 femur uppermost, and the tibiae and tarsi bent under against the thorax 

 and abdomen, the last pair extending beyond the fifth segment of the 

 abdomen, all yellowish white ; the wings were concealed by the legs, 

 and the back was bent and of a brown hue. The boring apparatus 

 was easily recognised in both these females. 



On the 20lh of April these two had moulted for the last time, but 

 for the first three days after they had not acquired the use of their 

 legs, and lay mostly on tlieir backs. A female made her appearance 

 from an unopened cocoon on the 24lh, and another on the 28th. These 

 were strong on their legs from the first, but did not fly, even when 

 placed in the sunshine. It is worthy of remark that during that year 

 my cocoons produced females only, and that in the following year 

 from eight cocoons I reared exclusively males. The latter all appeared 

 in the beginning of March, which is probably to be attributed to the 

 milder temperature. 1 have not found the larva since, and 1 never 



