CAUSES OF HYPERMETAMORPHOSIS 693 



and thorax, and then crawls out of it the "third larva," which only 

 differs from the ultimate stage of the second larva " in the somewhat 

 reduced size and greater whiteness." The insect in this stage is said 

 to be rather active, and burrows about in the ground, but food is not 

 essential, and in a few days it transforms into the true pupa state. 



These habits and the corresponding hypermetamorphosis are prob- 

 ably common to all the Meloidse, though the life-history of the other 

 species has yet to be traced. 



In the genus Hornia described by Riley, the wings of the imago 

 are more reduced than in any other of the family, both sexes having 

 the elytra as rudimentary as in the European female glow-worm 

 (Lampyris noctiluca). These, with the simple tarsal claws and the 

 enlarged heavy abdomen, as Riley remarks, " show it to be a degra- 

 dational form." 



Its host is Anthophora, and the beetle itself lives permanently in 

 the sealed cells of the bee, and Riley thinks it is subterranean, sel- 

 dom if ever leaving the bee gallery. The triungulin is unknown, but 

 the ultimate stage of the second larva, as well as the coarctate larva, 

 is like those of the family in general, the final transformations taking 

 place within the two unrent skins, in this respect the insect (Fig. 643) 

 approaching Sitaris. 



It appears, then, that as the result of its semi-parasitic mode of life 

 the Campodea-form or triungulin larva of these insects, which has 

 free-biting mouth-parts like the larvae of Carabidae and other car- 

 nivorous beetles, instead of continuing to lead an active life and feed- 

 ing on other insects, living or dead, and then like other beetles directly 

 transforming into the normal pupa, moults as many as five times, 

 there being six distinct stages before the true pupa stage is entered 

 upon. So that there are in all eight stages including the imaginal 

 or last stage. 



One cannot avoid drawing the very obvious conclusion that the 

 five extra stages constituting this hypermetamorphosis, as it is so 

 well styled, are structural episodes, so to speak, due to the peculiar 

 parasitic mode of life, and were evidently in adaptation to the re- 

 markable changes of environment, so unlike those to which the 

 members of other families of Coleoptera, the Stylopidae excepted, 

 have been subjected. The fat overgrown body and the atrophied 

 limbs and mouth-parts are with little doubt due to the abundant 

 supply of rich food, the protoplasm of the egg of its host, in which 

 the insect during the feeding time of its life is immersed. Since it 

 is well known that parthenogenesis is due to over, or at least to 

 abundant nutrition, or to a generous diet and favoring temperature, 



