THE AMEEICAN ENTOMOLOGIST. 



21 



more marked with black than those of the 

 female, it would not be very easy to distinguish 

 one from the oilier, but by the usual sexual 

 characters. Hence we have not thought it 

 necessary to give a figure of the male as well 

 as of the female ; whereas in the imported 

 species the two sexes ditt'er so essentially in 

 their coloration that, as already observed, a fig- 

 ure of one would give scarcely any idea of the 

 other. 



The larva of the J^ative Currant Worm Fly 

 (Fig. 11, a) is of a uniform pale green color, 

 without those black dottings which are always 

 found except after the last moult in the imported 

 species. Before the last moult, indeed, the head 

 is of a uniform black color, though it afterwards 

 has a good deal of green in front; but the body 

 remains throughout of the same immaculate 

 green shade. It diftcrs also in its habits from 

 the imported species, never, so far as we can 

 find out, going- underground to spin its cocoon, 

 but always spinning that cocoon among the 

 twigs and leaves of the bushes upon which it 

 feeds. 



This species agrees with the other one in being 

 double-brooded, the first brood of larvsB appear- 

 ing about the end of June and the beginning of 

 July, and the second brood from the middle of 

 August to the forepart of September. But in- 

 stead of the larvas of the second brood lying 

 underground iu their cocoons all winter, they 

 burst forth in the fly state from the beginning 

 to the middle of .September. Hence the female 

 fly is compelled to lay her eggs upon the twigs 

 instead of on the leaves; for if she laid them 

 upon the leaves, as is tlie habit of the imported 

 species, the second laying of eggs, which has to 

 pass the winter in that state, would fall to the 

 ground along with the leaves in the autumn, 

 and tlie young larvaj would starve when they 

 hatched out next spring before they could find 

 their appropriate food. Consequently, in the 

 case of this species, we cannot apply the method 

 of counterworking the other species which has 

 been already referred to. For we have parti- 

 cularly remarked that the very young larvas 

 were not gathered in great numbers upon one 

 particular leaf— as with the imported species — 

 but were distributed pretty evenly over the 

 whole bush. Neither did they bore the singular 

 holes through the leaf (Fig. 9), which render 

 the other species so easy of detection when 

 young. 



As will have been observed from the figures 

 given above, the Native species, besides the dif- 

 ferences already noticed, is only about two- 

 thirds the size of the other in all its states. Like 



the otlier, it infests both Currant and Goose- 

 berry bushes, but appears rather to prefer the 

 Gooseberry. Indeed there can be little doubt 

 that our native gooseberries formed its original 

 food-plant; for many years ago we captured a 

 single specimen in the neighborhood of Rock 

 Island, 111., in woods remote from houses, where 

 the wikl gooseberry was pretty abundant, and 

 there was no wild Red Currant. The species 

 was described in 18G6 by the Senior Editor* 

 from numerous specimens found stripping the 

 gooseberry and currant bushes in Davenport, 

 Iowa ; and it has since been reported to us by 

 Miss Marion Hobart, of Port Byron, N. Ills., as 

 so abundant in her neighborhood in 18C8 on the 

 gooseberries as to completely defoliate them 

 three times over, so that slie inferred — but we 

 think erroneously^that there were three dis- 

 tinct broods of them, one generated by another. 

 Mr. Jas. H. Parsons, of Franklin, N. Y., has in 

 a letter to us expressed the same opinion with 

 regard to the imported species. Probably both 

 parties have been deceived by what is a very 

 common occurrence with many leaf-feeding 

 larvEB. There is often a warm spell early iu the 

 year which causes a moiety of the eggs of a par- 

 ticular brood to hatch out. This is taken for 

 the first brood. Then follows a long scries of 

 cold weather, which prevents the other moiety 

 of the same batch of eggs from hatching out 

 till perhaps a month or six weeks afterwards. 

 When at last this moiety does hatch out, it is 

 considered by inexperienced persons as a dis- 

 tinct second brood. There is also very fre- 

 quently a very great variation, probably from 

 similar causes, in the time at which the same 

 batch of pupte burst forth into the perfect winged 

 state.' For example, out of a lot of 31 cocoons 

 of the second brood of the Imported Currant 

 Fly, all received by us at the same time from 

 Dr. Wm. M. Smitli of Manlius, N. Y., most of 

 the flies came out between June 26th and July 

 11th, but a few did not appear till tow\irds the 

 latter end of July and one linjfored on till 

 August 13tb. 



On Sept. nth, ISGO, we captured a single 

 female of the Native American species at large 

 in the City of Rock Island ; but the species has 

 not yet prevailed there to any noticeable extent, 

 so far as we have heard. In August, 18G7, A .H. 

 Mills, of Vermont, wrote to us about " a small 

 green worm " infesting the leaves of his Currant 

 bushes, which, as he was well acquainted with 

 the Imported species, was moMt probably the 

 Native American worm. And as long ago as 

 1858, a species of Sawfly was described in the 



* Practical Entomologist , I, pp. 122-4. 



