The Cabbage Root Maggot. 519 



" This little friend . . . was foaad in considerable numbers running 

 about among the cabbages and burrowing down beneath the soil in search of 

 maggots. Not only is it extremaly active in preying upon the magi^ots, 

 but it is also a true internal parasite feeding inside them and completing its 

 transformations inside the pupa case. In the hope of rearing this beetle, 

 16 larvae and pupae were taken from the root of a cabbage, where the per- 

 fect beetle had been seen and were inclosed in a breeding jar. From these 

 were reared 9 beetles and one fly, the remainder of the pupae dried up 

 without coming to maturity. In some of them, however, the immature 

 beetles were found when the cases were broken. When the beetle eats it 

 way out of the pupa-case it gnaws a ragged hole at one end quite differ- 

 ent from that made by the emergence of the fly I have 



generally been able to find a few of these beetles in beds of cabbages in- 

 fested by the Cabbage Maggot and upon one occasion bred a specimen from 

 the Onion Maggot." 



These accounts of the habits of this beetle indicate it works destruction to 

 the Cabbage Root Maggot both as a parasitic larva and as a predaceous adult. 

 Both Mr. Sprague's and Mr. Fletcher's accounts would seem to show conclu- 

 sively' thatthis Staphylinid beetle is a true parasite. And yet, closely allied 

 forms are known to have strictly pedaceous habits In 1888, Mr. Coquillett saw 

 a larva oi Maseochara valida " busily gnawing its way into a puparium of a 

 Syrphidfly. At the expiration of 24 hours it had completely buried itself in the 

 interior of the puparium, and I saw nothing more of it for a whole month, 

 when it issued through an irregular hole in the upper side of the puparium 

 and soon afterwards spun an irregular, thin, tough, white cocoon in the 

 bottom of the breeding cage. The beetle issued about 11 weeks later." At 

 the meeting of the Association of Economic Entomologists in 1891, Mr. 

 Schwarz, who has a wide knowledge of the habits of beetles, said that he 

 " considered the larva of these beetles not to be true parasites, but simply 

 predatory, . . . and stated, moreover, that the beetle larva has no ap- 

 proach to the parasitic habitus." 



Thus theoretically, this enemy of the Cabbage Root Maggot 

 should be purely predaceous in its habits, but practically the evi- 

 dence of competent observers seems conclusive that it is truly 

 parasitic. As we have not met with the beetle in our observa- 

 tions, we can offer no evidence in support of either opinion. The 

 evidence both pro and con, has been quoted in full, with the hope 

 that it will stimulate future observers to carefully investigate this 

 point whenever they may be fortunate enough to find this little 

 enemy at work. There is no doubt that man has a most potent 

 ally in this little beetle. 



The Cabbage Fly has still another enemy in the shape of a 

 mite, a species of Trombidium ; it resembles its near relative, the 



