142 ' THE ENTOMOLOGIST. 



of it. In the lowest Lepidoptera Aculeata (Adelidse), as Incurvaria 

 and Crinopteryx, we find only the 1st abdominal segment so fixed. 



In the higher Lepidoptera Aculeata, in Tischeria, and some 

 others, the first two abdominal segments are fixed. Then we 

 come to the great mass of species with Pupae Incompletae, in 

 which the first three abdominal segments are fixed. These 

 include the true Tinese, Cossidae, iEgeriadse, all the Tortrices and 

 their allies, &c., as well as the Pterophorina, which are otherwise 

 specialized. This seems to have been the structure of pupa that 

 was most successful as a Pupa Incompleta — at any rate, it is the 

 most popular. We then come to a Pupa Incompleta with the 

 first four abdominal segments fixed. This is the pupa of the 

 Gracilariadae . 



At this point in the evolution most lines of advance seem to 

 have ceased to remain as Pupae Incompletae, and to have become 

 Pupae Obtectae, i.e. they ceased to emerge from their puparia, 

 and they acquired fixity in the 7th segment in the male, and 

 became of the type of Pupa Obtecta that ranges throughout all 

 the Macro-Lepidoptera, the Pyrales, Gelechids, Depressariads, 

 Yponomeutids, CEcophorids, &c. 



A Pupa Incompleta, with only two free segments (5 and 6, 

 female ; 5, 6, 7, male), seems to have been an unsatisfactory 

 organism, and only obtained a permanent existence in the group 

 we are considering — the Gracilariadae. 



It seems to me extremely probable that amongst the many 

 exotic families of Micros, of which I am entirely ignorant, there 

 is one or more with this pupal structure, attained quite in- 

 dependently of the Gracilariads ; since it is a form, so to speak, 

 quite in the highway of ordinary evolution in the Lepidoptera. 

 Up to the present, however, I have not met with such a form. 



The process of emerging from the puparium must be less 

 easily performed with only two movable segments, and the ten- 

 dency must have been very strong to go right forwards at once 

 into the obtect condition. 



The pupal condition of the Gracilariadae is as definite in 

 separating them from all other groups as is the larval one. And, 

 of course, each of these is much more important, taken with the 

 other, than it would be by itself. The larval specialization is so 

 remarkable and unique, that by itself it may be taken as fairly 

 sufficient to define the group, when we consider that there is no 

 strong point — no point at all, in fact — pei- contra. The pupal 

 condition is of very nearly the same weight in associating the 

 species within the group, and delimiting them from others. 

 Either by itself is adequate for this purpose ; the two, taken 

 together, are of course not simply twice as potent, but at least 

 four times as potent. 



(To be continued.) 



