Cephidae 485 



mately 80 ° F. This was accomplished by the use of a large pasteboard 

 box in which was placed an electric bulb of sufficient voltage to keep the 

 temperature within at about that temperature, thus serving as an in- 

 cubator in which the breeding jars were kept at all times. Moist sand 

 was placed in the jars and the bottom ends of the pine sticks were 

 imbedded in the sand; the upper ends were coated with paraffin. This 

 method of handling the breeding material conserved the moisture long 

 enough, under high temperature, to allow the broods to develop suc- 

 cessfully. 



As this species usually breeds only in the smooth bark of pine it was 

 necessary to select pine limbs from % to 2 inches in diameter. It was 

 possible tu get larger-sized limbs having smooth bark but they were 

 not so easily handled in the breeding jars. 



Order hymenoptera, Family cephidae 



A METHOD FOR BREEDING CEPHIDAE 



Donald T. Ries, Ithaca, N. Y. 



IN ORDER to obtain data on the life history and habits of the wheat- 

 stem sawflies, Cephus pygmaeus and Trachelus tabidus, the writer 

 developed the following method for the former species and later used 

 approximately the same method for the latter species. It is probable 

 that this method would also be satisfactory for other related herbaceous 

 stem-borers. 



At first a large cage 6 ft. long by 4 ft. square was constructed and 

 covered with cheesecloth. Late in the fall infested stubble was col- 

 lected and planted in the cage. In this same cage winter wheat was 

 sown and allowed to develop, the cage being covered with cheesecloth 

 until all danger from Hessian fly infestation was past. The covering was 

 then removed to give as nearly natural conditions as possible and re- 

 placed in the spring before time for emergence of the adult insects. 



Later these cages as well as the small Hadley cage (12" x 12" x 24") 

 were used indoors with excellent results. In these the wheat was grown 

 in large 12" flower pots and the adults introduced. By this method 

 parasitism of the sawfly larvae by adult parasites which emerge from 

 stubble was eliminated. When one female was introduced in each, the 

 large cages served for making egg counts, as a single female usually 

 deposits only one egg in each stem. Inasmuch as a large cage may 

 contain as many as 1,000 stalks of wheat it is easy to obtain a fairly 

 accurate egg count. 



Because adults in the field were noted feeding on the pollen of wild 

 mustard, Brassica vulgaris, plants of this species were introduced into 



