346 NATURAL HISTURY OF ARTHROPODS. 



pure oantbaridiu for use in preparing medk-ines. Pure eanthariiliu (C'H'^O-) is insolu- 

 ble in water, sparingly soluble in alcohol, and readily soluble iu ether ; with the latter 

 tluid it can be extracted from eantharides, and then purified by separation from the 

 accompanying oils and by crystallization. Cantliaridin crystallizes in colorless, four- 

 sided prisms or lamiiue. Although Lijtta vesicatoria (the so-called Spanish fly) is the 

 species generally used in medicine, other Meloid;e — among whicli may be mentioned 

 species of Jli/labris, Epicauta, nnd Mticroliasis — have been used, and give a larger 

 percentage of cantharidin than is obtained from Lijtta ctsicatoria. Probably all 

 species of Meloidie are vesicant to a greater or less degree. In ])reparing Spanish 

 flies for the market, they are killed by heat, and then rapidly dried. The extent to 

 which these insects were used in early times is indicated by the eighty-five citations, 

 giveu by Jordens iu 1801, of works in which considerable mention of 

 eantharides is made. 



Species of Meloidie are injurious as well as useful; a number of 

 species devour potato-leaves, both in this and in other countries. In 

 Italj' Lytla enjthrocephala sometimes devastates potato-fields ; in this 

 country Eplcauta cinerea, E. pensylcanica., E. vittata, and JIacrobasis 

 unicolor attack potatoes in addition to other plants. E. vittata and 

 Fig. 388. — £■/);- 31. unicolor are, however, known to iirev at times upon the larvie of 



cauta vittata. i ^i i -i 



the Colorado potato-beetle. 

 The mode by whicli the Meloidie dcveloji ivtnw the egg to the imago has been 

 termed liypermetamorphosis. In brief, it is as follows : The egg, which is laid in the 

 ground, hatches into an active larva, called the triungnlin, from the name triungulinus 

 given to it by Dufour in 1828. These triungulins, or first larvfe, run actively abotit; 

 some of them ascend plants, others live in sand, their mode of life varying according 

 to what their subsequent history will be. The triungulins which climb plants, as do 

 those of Mdoe, remain about the flowers, attaching themselves to flies, bees, and wasps 

 that visit the flowers for honey, and were described by several early naturalists as bee- 

 lice. The triungulins of Meloe are sometimes so abundant, according to Dr. C. V. 

 Riley, on hive-bees, as to worry them to death, although he believes these triungulins 

 " cannot well, in the nature of the case, breed in the cells of any social bee whose 

 young are fed by nurses in open cells." Tliose triungulins that attach themselves 

 to such wild bees and wasps as are fitted to further their development are carried by 

 these Hymenoptera to tjieir nests, wherein they go from the bee to its egg in a cell, 

 and devour the egg, after which a moult takes place, and the triungulin, fornu'riy so 

 active, is converted into a clumsy second Larva, which feeds upon the honey ju-ovided 

 for the young hymenopteron. The second larva then partially moults, remaining, how- 

 ever, within its skin, and becomes a pseuilo-]iui)a. A third larva follows by similar 

 l)artial moulting of the jiseudo-pupal skin, and finally a triu- j)ui)a and imago. Certain 

 triungulins, or first larva% which wander about the ground, as do those of Epicauta 

 and Macrohdiih, have been found by Dr. C. V. Riley to feed ujion the eggs of the 

 Rocky jNIountain locusts {Caloptenus sjiretus) and upon eggs of C. differentiulis. The 

 triungulin which devours locust eggs moults to enter what Dr. Riley has called, on 

 account of its resemblance to larvse of Carabid;^^, the " carabidoid stage of the second 

 larva> ;" another moult transforms it to what the before-mentioned author has termed, 

 because of resemblance to larvae of Scarabieidaa, the " scarabjeidoid stage of the 

 second larva;" still another moult*]irodnces what, following Dr. Riley's nomenclature, 

 is the " ultimate staoe of the second larva." Leaving now, for the first time, the 



