250 



PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 



it betrays a distinct partiality for anything that savors of the brown- 

 tail moth. It is thereby led to seek out the molting webs of the 

 brown-tail caterpillars in the spring and consequently comes into 

 contact with the Apanteles cocoons. 



THE SARCOPHAGIDS. 



There has been considerable controversy in the past concerning 

 the habits of the Sarcophagidae, and a wide difference of opinion as 

 to whether they were to be considered as truly parasitic, or whether 

 they were merely scavengers, attacking and feeding upon insects 

 which had died through some other cause. In the 

 case of those species which are reared from grass- 

 hoppers there seems to be no further question that 

 they are to be classed as true parasites or at least 

 that they are as truly parasitic as many of the more 

 degraded among the hymenopterous parasites. This 

 seems not to have been proved of any of the species 

 which are found within the pupae of the larger 

 Lepidoptera. 



If judgment were to be based upon the occurrence 

 of sarcophagids in the shipments of gipsy-moth 

 fig. 56.— Gipsy -moth p U pge from abroad, it would certainlv be judged that 



pupa, showing exit , , . , . . ,-,, . 



hole left by Mono- the sarcophagids were parasitic. I heir puparia 

 dontomerus xreus. (pj # XX, fig. 3), have frequently outnumbered the 

 tachinid puparia, and even the tachinid puparia and 

 hymenopterous parasites together. Unfortunately, there is nothing 

 known of the circumstances under winch this material was collected 

 in any instance, and for all that is known to the contrary, the 

 sarcophagids actually entered gipsy-moth pupae which had been at- 

 tacked and killed by another parasite, Chalcis for example, and by 

 feeding, first upon the unconsumed contents of the pupal shell, and 

 later upon the body of the true parasite, which might be destroyed 

 either through accident or design on the part of the intruder, would 

 become, in effect, secondary parasites. 



If judgment were to be based upon the results of a quite elaborate 

 series of investigations into the relations between the native sarco- 

 phagids and the gipsy moth in America, it would unavoidably be to 

 the effect that these sarcophagids were scavengers and nothing more. 

 We are confronted with conflicting evidence, presented by a much 

 greater abundance of sarcophagids associated with the gipsy moth in 

 Europe than is similarly associated with it in America, which is sug- 

 gestive of two things: Either the sarcophagids are associated with the 

 gipsy moth because they are parasitic upon it or because of the pres- 

 ence of its parasites, which is quite as reasonable an explanation. It 

 will require much careful work in Europe before it will be possible to 



