30 THE CANADIAN ENTOMOLOGIST. 



NOTES ON THE LIFE-HISTORY OF THE BLISTER-BEETLES 

 AND ON THE STRUCTURE AND DEVELOPMENT 



OF HORNIA. 



BY PROF. CHAS. V. RILEY. 



(Abstract.) 



At the Hartford (1874) meeting of the Association, Mr. Riley described 

 the newly-hatched larva of some of our common Blister-beetles ; but all 

 attempts to trace their habits had proved futile, both in this and other 

 countries, until 1877, when he discovered that they preyed on the eggs of 

 locusts (Acrididre). In a paper published in the last volume of the 

 Transactions of the Academy of Sciences, of St. Louis, the life-history of 

 several of our common Blister-beetles is traced. The present paper gives 

 a brief resume of the facts there recorded, showing that the beetles 

 belonging to the genera Epicauta and Macrobasis go through the same 

 curious hyper-metamorphoses as do other species of the family Melotdce, 

 and especially as Melo'c and Sitaris were already known to do. The larva 

 hatches as an active, pale-brown, long-legged creature, termed triungulin 

 on account of its three-clawed tarsus. It then changes to what Mr. Riley 

 calls the Carabidoid stage, in which it is white, less active and fleshy ; 

 then to what he calls the Scarabceidoid stage, in which it is still more 

 degraded and clumsy ; then hardens to what he calls the Coarctate larval 

 stage, in which it is perfectly helpless and resembles the puparium of 

 many Diptera ; then to the final larval stage, in which it is again white 

 and soft and more or less active ; then to the true pupa state ; and finally 

 to the beetle ; existing, thus, in eight distinct states (including the egg), 

 instead of the four in which ordinary insects occur. 



The paper is principally devoted, however, to the life-history of a very 

 anomalous, wingless genus of this family, the Hernia minutipennis Riley. 

 This insect is degraded and subterranean, and was found in the cells of a 

 common Mason-bee, the Anthophora abrupta Say. Its life-history, which 

 was not known at the time thespecies was described, lias been completely 

 made out by Mr. Riley during the past summer. The eggs, which are laid 

 loosely in the burrows of the bee, hatch during the early part of June. 

 The triungulin is extremely active, and, in all essential characters, very 

 similar to that of Sitaris, one species of which, in Europe, likewise 



