Packard : Transformations of Hymenoptera. 155 



NOTES ON THE TRANSFORMATIONS OF THE 

 HIGHER HYMENOPTERA.— I. 



By a. S. Packard. 



The following descriptions of the larval and pupal stages of some 

 of our more common Hymenoptera belonging to the fossorial families, 

 together with the wasps and bees, were drawn up over twenty years 

 ago and were preserved in the hope of adding others. But lack of 

 time and material has prevented such additions and what few notes 

 have been gathered are now offered for publication. The descriptions 

 are, so far as possible, comparative, as this is especially needful in the 

 case of larvse whose mode of life is so similar, and which therefore pre- 

 sent very slightly marked specific as well as generic characters. In no 

 group of animals, perhaps, are there such slight larval characteristics as 

 in those of the Hymenoptera, the phytophagous forms being excepted. 

 This is evidently due to their living confined in closed cells, to their 

 lack of the necessity or power of locomotion, and to the fact that im- 

 mediately after birth they can feed on food, whether vegetable, such as 

 pollen, or the bodies of other insects or spiders stored up for them by 

 the prevision of their parents. They live in total darkness, hence are 

 eyeless ; they have no enemies to shun, hence have no defensive spines 

 or armature of any kind. The reduction in the limbs and mouth-parts, 

 and the lack of any differentiation in form, ornamentation, or color 

 of the integument ; even the undeveloped proctodseum, all tend to 

 prove that the larval forms of these Hymenoptera are due to modifica- 

 tions from simple disuse, for their embryology shows that they have de- 

 scended from insects whose larval forms were out-of-door feeders, 

 probably like those of the saw-flies, and provided like them with ab- 

 dominal as well as thoracic legs. 



It is to be hoped that our entomologists will hereafter pay more at- 

 tention to the habits of our wasps and bees, for the wonderful differen- 

 tiation of the bodies of the adults is correlated with their varied and 

 striking modes of life and their high degree of intelligence. 



Pompilus funereus Sf. Farg. 



Larva. — This larva is with some hesitation referred to the above 

 species, but it belongs to a common New England species. The head 

 IS round, scarcely longer than broad; the surface of the front not very 

 convex, being much shorter and broader than in Polistes. Eyes on the 



