NATURAL HISTORY SOCIETY OF GLASGOW. 297 



roundish or oval ; and tlie colour is dark purple, or very dark 

 pink above, and green underneatli. When very young they are 

 of a uniform green colour. I had no means of observing how or 

 when the eggs are deposited ; but from analogy it seems probable 

 that the female lays them when the leaves are bursting out ; and 

 this conclusion is also justified by my finding, on very young 

 leaves, galls in progress of development. 



The habits of the larva are identical with those of the familiar 

 N. Vallisnieri ; but, unlike the larva of that insect, it does not 

 make arhole on the underside of the gall at one end, for the expul- 

 sion of the ''frass." It devours the gall very closely; and when it 

 has become full fed, its habitation is reduced to a mere thin bladder, 

 all but the skin having been devoured. I noticed on some of the 

 leaves galls which had every appearance of being composed of 

 two galls amalgamated, but only one larva could be found. It 

 was also interesting to notice that often on the same leaf two 

 galls would be found, in one of which the larva would be far 

 more advanced in its development than its neighbour; yet the 

 eggs must have been laid at the same time. In one instance a 

 larva was still in the ^g^, whilst the other was in the commence- 

 ment of the second moult. 



When full fed the larva has the head of a white colour, more 

 or less marked with fuscous above ; the eyes are placed in brown 

 spots ; the mouth brown. The feet are greenish white ; and over 

 the first six there is a black band over each ; and they have also 

 their claws black. When the creature is feeding the dorsal vessel 

 is green ; the rest of the body is of a dirty white colour, slightly 

 tinged with green, and covered with a few hairs. The body 

 tapers toward the end ; the segments project much at the sides. 

 The abdominal feet are invisible from above, and, to a certain 

 extent, laterally, by being hid by the overhanging folds of the 

 body. The colour of the head is subject to some variation in the 

 amount of fuscous with which it is marked. 



From the above description it is at once evident that the simi- 

 larity of the larva of femoralis with that of Vallisnieri is very 

 close indeed. 



As already remarked the galls were found in June ; and by the 

 middle of July all the specimens I brought home had spun their 

 cocoons ; and this appears to be the usual habit, for T visited the 

 locality in which they were first discovered last year, on the 18th 



