120 



THE AMERICAN ENTOMOLOGIST. 



shown by Mr. B. Hulick of Michigan, ac- 

 cording to Prof. Cook. Mr. Hulick found 

 the empty flaxseeds in volunteer wheat 

 in September. On Prof. Cook's express- 

 ing some doubt whether the fly had 

 issued, suggesting that it might be the 

 parasites that had eaten the fly and 

 come forth, as the time appeared to him 

 too short, Mr. Hulick at once jjlanted 

 some of the volunteer wheat, still contain- 

 ing the flaxseed in close jars, and "saw 

 many of the flies issue, and more, had eggs 

 laid by these flies on the same wheat in 

 October. Mr. Hulick showed these flies 

 and their eggs to several of his neighbors. 

 In this case the eggs were deposited in 

 July, the flaxseed state assumed in Sep- 

 tember, from which came a third brood of 

 flies in October. This is certainly a very 

 im])ortant matter, as it shows that three 

 broods are possible under favorable con- 

 ditions ; that while the flies may, nay 

 generally must, wait till September to de- 

 posit eggs, they only want opportunity to 

 breed their mischief much earlier, even in 

 July or August, and thus propagate a late 

 brood of flies, which will be in readiness 

 for even the latest sown wheat. No doubt, 

 too, as in the case of all insects, varying 

 degrees of heat or cold will accelerate or 

 retard the various transformations."* 



MoJe of egg laying (see Fig. 46, e, the fly 

 of its natural size engaged in laying eggs). 

 The mode of oviposition has thus been 

 described by Mr. Herrick : "The eggs 

 are laid in the long creases or furrows of 

 the upper surface of the leaves (/. e. the 

 blade or strap-shaped part) of the young 

 wheat plant. While depositing her eggs, 

 the insect stands with her head towards 

 the point or extremity of the leaf, and at 

 various distances between the point and 

 where the leaf joins and surrounds the 

 stalk. The numlier found on a single 

 leaf varies from a single egg up to thirty, 

 or even more." Prof. Cook says that "the 

 fly very rarely lays more than three eggs 

 at one time, without change of position. 

 She more frequently lays two, and gen- 



*A Lecture before the Farmers' Institute at Paw Pav 

 Mich., 1878, p. 9. 



erally but one. In case she lays but one 

 it takes less .than a quarter of a minute, 

 and less than half a minute to lay three, 

 when they are all laid without a change of 

 position on the part of the fly. After 

 laying she seems to draw in her ovipositor 

 soon to extend it again, at the same time 

 crowding into it the one, two or three eggs 

 that are next to be laid. She then flies to 

 another leaf, alighting usually, not always, 

 with head towards the leaf. She then 

 appears to wipe the eggs oft' the jointed 

 ovipositor. She really crowds the egg till 

 the end touches the leaf, when, by friction 

 of the leaf and adhesion of the egg, the 

 latter is held fast, while the egg-tube is 

 withdrawn. If the second and third are 

 to be laid, she repeats the operation, after 

 which she retracts her ovij^ositor, restocks 

 it, and in a trice is depositing the fatal 

 germs on another leaf. I say usually on 

 the upi)er surface, for occasionally eggs 

 are laid on the stalk, and sometimes on the 

 under side of a leaf. I have observed 

 that the fly often makes unsuccessful' ef- 

 forts to cause the eggs to adhere on the 

 outer face of the leaf before she succeeds. 

 I have seen a fly work thus for two minutes 

 before success crowned her efforts."* 

 ****** 



Prof. C. V. Riley thus described the pro- 

 cess in the New York Weekly Tribune of 

 March 7th, 1878: "I have very carefully 

 studied the oviposition of the Hessian Fly, 

 closely observing the female in the act on 

 several occasions; and as accurate observa- 

 tions on this point are not easily made, I 

 herewith transcribe my notes of several 

 years ago: 



Eggs deposited in irregular rows in the longitu- 

 dinal cavities and depressions of wheat stalks 

 between the stalk and sheath, when this is loose, 

 or on the leaves between the natural ridges or 

 carina: of the upper surface, this last being the 

 common habit. Ordinarily there are from five to 

 ten in a row, but sometimes more. Each egg is .02 

 inch long, cylindrical, rounded at each end, soft, 

 translucent, and pale orange-red in color. Be- 

 fore hatching the pale sides of the inclosed larva 

 show through the shell. Larva hatched in four 

 days, crawls down leaf to base of sheath, which 

 on young grain is at crown of root. The orange- 

 red color is soon lost, and the larva becomes 



*Lec. cit. p. 7. 



