8 THE CABBAGE MAGGOT. 



Naturally these dates will vary from year to year, de- 

 pending' upon weather conditions. 



Prcdaceoiis and Parasitic Enemies of the 

 Cabbage Maggot. Reference to the colored 

 plate will demonstrate the fact that the life 

 of the cabbage maggot is beset with dangers 

 from this source. We know of at least one 

 Fig. 5.— A parasite of other Coleooterous enemy, a Staphylinid, 



the cabbage maggot. , \ / ^ -' 



(.Author's iiiustra- uot ODservcd hcrc, and hence not figured. 

 There are many other predaceous and para- 

 site forms preying- upon this larva. The Cynipid para- 

 site, Pseudeucoela gillcttei, Ashm., shown enlarged as Fig. 7, 

 col. plate, was collected in a maggot's burrow. It has long- 

 been known as a parasite of this species. Fig. 12 Plectisciis 

 sp., (identified by Dr. Skinner) also enlarged was bred from a 

 puparium of a cabbage maggot. The Carabid beetles, Pteros- 

 tichus coracinus, Neum., Fig. 12 col. plate; P. leucoblandus. 

 Say, Fig. 8, col. plate; Agomoderns pallipes, Fab., Fig. 10, col. 

 plate, as well as Amara impuncticoUis, Say, Fig. 9, col. plate, 

 were continually observed in large numbers in all cabbage fields 

 where the fly occurred. These were collectd, brought into the 

 laboratory, and immediately fed with maggots. The fact 

 that they at once pounced upon and consumed the maggots 

 given them would seem to warrant us in placing them among 

 the enemies of the maggot, though not, as far as I am aware, 

 referred to as sucli in previous writings. The following- 

 beetles were also observed in such nunibers in cabbage fields 

 as to lead me to suppose that they may also prey upon the 

 cabbage maggot, though not observed to do so, Heterothops 

 fiimigatus, Lee, Lathrobicem anali, Lee, belonging to the 

 Staphylinidae, and the Carabid, Bcmbidiniu -/-iiiaculafiis, 

 Linn. 



Perhaps its most persistent predaceous enemy is the red 

 mite, Trombidium scabnnii, Say, Fig. 6 col. plate, which we 

 have observed sucking incredible numbers of eggs of Phorbia. 

 On May I5tb an assistant in the field reported this mite as 

 very active, averaging about two to a plant, and occasionally 

 four or five were observed about one plant. The activity of 

 this mite at this date was evidenced by the fact that a large 

 per cent of the eggs examined had been sucked. "Some times 

 there would not be a single good egg around a plant out of 



