16 



prolegs on the first abdominal are in process of being lost. In some 

 species of Nepticulids the primitive anal claspers are more developed 

 and more used than in others. There are no crotchets on any of 

 these prolegs. Thus, in the Nepticulid larva, we see no true thoracic 

 legs at all, and yet the imago has very strong legs, and makes very 

 active use of them. 



In Cemiostoma laburtiella we find the newly hatched larva without 

 any legs. In the second instar the cushion-like pads appear on the 

 meso- and metathorax, while in the third instar the larva has a small 

 pair of pads on the prothorax, and larger pads on the other two 

 thoracic segments ; each of these pads bears a small chitinous claw. 

 The third, fourth, fifth and sixth abdominal segments have prolegs, 

 of which the two middle pairs are larger than the others. These 

 two larger pairs are so strong that the larva can stand on them alone, 

 elevating all the other segments. There are no crotchets on these 

 prolegs. In the fourth instar the arrangement is the same, but the 

 prolegs bear one circle of from fourteen to sixteen crotchets, while 

 the anal claspers are well developed, and possess the usual three 

 quarters of a circle of crotchets. 



The larva of Chrysopora hennanniella leaves the egg already pro- 

 vided with three pairs of thoracic legs, but has no ventral prolegs or 

 anal claspers. In the second instar it has developed both prolegs 

 and claspers, but these are without crotchets. In the third instar the 

 prolegs are larger, while in the fourth instar they are still slender, and 

 only have a few crotchets, not a complete circle. 



The few species of the genus Coleophora, which I have seen in the 

 first instar, are all provided with legs, prolegs, and claspers before 

 leaving the egg. In this genus, however, the ventral prolegs appear 

 to be a very unstable quantity, in respect to both the 'number of 

 pairs and number of crotchets. Some species have only three pairs, 

 and others four pairs of ventral prolegs, while the number of 

 crotchets to each leg often differs considerably, even in the same 

 larva. I remember examining a larva of Coleophora genistcp which 

 had a different number of crotchets to each leg, one of the legs 

 having no crotchets at all. The weakness of the prolegs in the 

 genus Coleophora is no doubt accounted for by the case-bearing 

 habits of the larvae. When climbing about the plants they feed on 

 they carry the sack with them, and use only the thoracic legs as a 

 means of progression. The anal claspers are well developed, and I 

 believe the case is chiefly held by them, as I have elsewhere stated. 

 I have taken many species out of their cases for a while, and found 

 that they all crawl about with their thoracic legs, without making 

 any use of the prolegs at all. 



The only member of the Pyi-alidce of which I know the first 

 instar is Scoparia 7miralis. Mr. South kindly gave me eggs of this 

 species, and I noted that the larva on hatching was provided with 

 legs, prolegs, and claspers, and was very active. 



Many Noctuid larvae when quite young make very little use of the 



