PARASITES OF GIPSY-MOTH PUPJE. 253 



tience, but are none the less necessary if we are ever to know all that 

 is to be known about the subject. 



None of the beetles mentioned is likely to attack the later-stage 

 caterpillars, but among the larger Carabidae is to be found a variety 

 of species which are not only able, but more than willing to destroy the 

 full-fed caterpillars and pupae whenever opportunity offers. There are 

 many such in Europe which do not occur in America, and altogether 

 a considerable number of different species has been received from 

 abroad and tested as to ability to assist in the control of the gipsy 

 moth in this country. 



Three characteristics in addition to ability and willingness to attack 

 the gipsy moth are necessary if the introduction of a beetle is to be 

 seriously undertaken as an economic experiment. It must breed at 

 the proper season of the year, so that its larvae may receive the ad- 

 vantage of the practically unlimited food supply which the present 

 superabundance of the gipsy moth gives; it must be able to with- 

 stand the rigors of the New England climate, and not only the adult 

 beetles but their young must be arboreal in habit. An abundance 

 of species both native and foreign will feed freely upon the gipsy 

 moth in confinement, but of these only a few will seek out the cater- 

 pillars or pupae in the situations in which they are to be found in 

 America. The adults of a portion of this number do habitually climb 

 into the trees in search of their prey, but not all such are similarly 

 arboreal during their larval stages. Of those which are arboreal, or 

 which appear to be arboreal, during all of their active life, a part 

 appear to breed at the wrong season of the year and another part do 

 not extend their range into a sufficiently high latitude to make them 

 effective as enemies of the gipsy moth. There is not a single species 

 native to America which meets all of the delicate requirements of the 

 situation, but such a species has been found abroad in Calosoma syco- 

 pTianta L. (See PL I, frontispiece, adult eggs, larvae, and pupa.) This, 

 of all of the numerous species of predaceous beetles which have been 

 investigated at the laboratory, bids fair to be of real assistance in 

 the fight which is being waged. 



Like all the larger carabids inhabiting the temperate regions, this 

 species is terrestrial during a considerable portion of its life cycle, but 

 both adults and young, which are equally voracious, climb freely into 

 the trees in search of their prey. The eggs are deposited in the earth, 

 and the young larvae upon emerging are possessed of a remarkable 

 vitality and sufficient strength and cunning to enable them to seek 

 out and successfully to attack, when found, the largest and most 

 active of the gipsy-moth caterpillars. They also attack the pupae 

 with even greater freedom, and once ensconsed within such a mass 

 of pupae as is frequently encountered in partially protected situations 

 upon a badly infested tree, will rapidly complete their growth without 



