174 



female of which wa.s taken by Mr. Webster, at Lafayette, lud., ou 

 wheat. 



This species may be recoguized by its being entirely black in both 

 sexes, which easily separates it from both D. arveusis and D. collaris. 



NBMATUS (MESSAf) MARYLANDICUS NORTON. 



(Syn. Nematus aureopectus I^orton.) 



Of all the Saw-flies found to breed on wheat, etc., perhaps the most 

 interesting species, both on account of its numbers and of the interesting 

 question of generic relationship which it presents, is the one named 

 above. This Saw-fly has been carried through two successive genera- 

 tions in conflnement, which experience, together with notes and ob- 

 servations made in the field, affords a pretty full knowledge of its life- 

 round and habits. 



Larvae evidently of this species collected on wheat were received 

 June 6, 1884, from Mr. Webster, from Normal, 111. Additional larvte 

 found feeding on timothy were sent by him from Oxford, June 23, of 

 the same year, and still another lot found on grass was received from 

 the same place May 28, 1885. No adults were obtained from these 

 specimens, and larviB of the first lot only were saved. 



July 25, 1884, Mr. Lawrence Bruuer forwarded us two larvae collected 

 July 7 in Holt County, Nebr. These are closely allied, if not identical, 

 with the Webster material. 



Mr. Webster had had better success in rearing the adults from the 

 larvae collected in 1884, and forwarded us eggs May 4, 1885, deposited 

 in a blade of wheat by reared specimens. Additional eggs, in a living 

 wheat i^lant, were received from Mr. AVebster a little later, and from 

 these two perfect insects were eventually obtained. Mr. Webster also 

 successfully reared adults from eggs deposited in confinement by reared 

 specimens. 



The habits of this insect may be summarized as follows : 



The adult insects (Fig. 14, e, male; /, female) appear during the lat- 

 ter part of April and first of May, the males antedating the females sev- 

 eral days, as is the rule generally with Tenthredinidai. In nature the 

 flies do not emerge much before the last week of Aj^ril, as shown by the 

 fact that repeated sweepings of wheat fields in the middle and latter 

 half of April failed to secure any adults. In the breeding cage speci- 

 mens appeared somewhat earlier, or from April 15 to May 1. 



The eggs, when first laid, are four-fifths by one-fifth millimeter, and 

 of a light green color. They are inserted to the number of two to five 

 or more togetlu^r along the edge of the wheat blades and just beneath 

 the epidermis (Fig. 14, a a). Some fifteen or sixteen days elapse before 

 hatching, during which period the eggs increase very considerably in 

 size 



