Life History of Hesperia sidae, Esp. 573 
spiracles, but they are quite round and have no visible vent. No 
hairs grow from them. 
The hairs are slightly swollen at their free extremities. 
The larva of H. sidae has a habit of ejecting its excre- 
ment with violence, throwing it a considerable distance 
away. I observed this operation on several occasions. 
The excrement was expelled gently until nearly the 
whole mass had appeared, then suddenly it was shot 
away, falling as nearly as possible 50 centimetres from the 
larva. 
I did not notice any movement on the part of the larva 
which would account for this, but Dr. Chapman tells me 
that Hesperid larvae are provided with an internal comb 
which enables them to get rid of their excrement in this 
way. The comb must be worked by a strong muscle. I 
had the larva out of its tent when this performance took 
place, but when inside the tent the end of the body is no 
doubt pushed out, and that would account for the very 
little frass found in the nests. There was particularly 
little in the spring tent in which the larva has been living 
since it left its winter quarters. The larva was taken out 
of its tent, early in April, to be photographed. This was 
not an easy matter, as it is very restless when interfered 
with, and seeks to hide itself under the leaves, especially 
when exposed to sunlight. 
As soon as the operation was over it was put back into 
the tent, but it did not stay there this time, for I found, a 
day or two afterwards, that it had made a new, roomy 
dwelling-place. To do so it had bitten right through the 
stems of two leaves, arranging them upside down to fill up 
gaps, and binding them with strong silk strands spun on 
the inside, to the other leaves entering into the composition 
of the tent. 
On April 14, Dr. Chapman, searching on the Potentilla 
hirta plants in the Plan du Pont valley, found a 4th stage 
larva of H. sidac in its tent. It was small, about the size 
of my larva when it went into winter quarters last Novem- 
ber. The tent it was in was not a winter nest but a new 
spring tent. 
It seems probable from this that the insect passes the 
winter normally in the 3rd or 4th stage, but, as the larva 
subsequently proved to be ichneumoned, it can hardly be 
regarded as a normal larva, and may have been retarded 
