THE AMERICAN ENTOMOLOGIST. 



81 



THE DROr-WORM AGAIN. 



Dear Sir: — Ireadyonr account of ilic Drop- 

 worm {Thyridopteryx ephemerw/ormis) with a 

 great deal of interest, which in the main cor- 

 responds with my own experience, but lliere 

 are some facts, in connection witii tliis insect, 

 which seem to have escaped yonr ob-crvation, 

 or wliich difler in some measure from mine. I 

 commenced my observations in 1849, and con- 

 tinued them for two or three years. A large 

 linden tree grew near the window of the room 

 in whicli my observations were made, some of 

 the branches reaching quite to the window-sill, 

 and this tree must have had some thous-ands of 

 this insect upon it lu this situation, the young 

 insects came forth from the follicle, from the 

 2'>th to the oOth of May, each one letting itself 

 down by a separate minute silken cable, and they 

 formed their first cone-shaped cases out of the 

 epidermis of the bark on the branches. Those 

 that were excluded in my room, formed them 

 out of lime on the walls, leather on the backs of 

 some of my books, and straw-matting on the 

 floor. Some of the females, that were not im- 

 pregnated by the males, did leave the follicle 

 entirely, without ovipositing, and 'had a feeble 

 power of locomotion, on a plain horizontal sur- 

 face, moving two or three inches during the 

 course of half a day. This was done by eloiiga- 

 tions and contractions of the body, maggot-like, 

 but less active. Immediately \\\\q,i\ the males 

 evolve from the pupa, in a state of nature, their 

 wings are not glassy, except a very small por- 

 tion near the outer margin. They arc opaque, 

 being covered with a dark coating of the mealy 

 substance which distinguishes the Lepidoptera, 

 but they soon become transparent, by the action 

 of flight. Those that evolved in confinement 

 were nearly always glassy, especially after they 

 had attempted to make their escape. The late 

 Major LeConte confirmed this observation of 

 mine by his own experience. Again, have \ on 

 ever witnessed the male in the«c<of impreg- 

 nating the female? I have, in at least twenty 

 \ instances, and in no case, immediately , after he 

 withdrew his abdomen from the follicle of the 

 female, did her body protrude from the pupa- 

 rium. It had the T-sbaped opening on the top 

 of the thorax, but the entire body of the female 

 , remained within it. The act of protrusion was 

 f always simultaneous with the act of oviposi- 

 tion. In fecundating the female, the male in- 

 troduces his abdomen into the opening at the 

 lower end of the sack, as far as his wings will 

 admit it, and he remains thus from fifteen to 

 twenty minutes. It is true that the abdomen 



of the male is cai)ablc of a great; elongation, but 

 by stretching it artificially to its utmost exten- 

 .sion, I never, by measurement, could reach any 

 way near the anal extremity of the female, which 

 you know is, at this time, at the opposite end 

 of the sack, and which, according to your quo- 

 tation from Harris, would be utterly impossible, 

 unless there existed a long thread-like sexual 

 organ— fully the length of the whole extended 

 body — sufliciently attenuated to pass between 

 the body of the female and her pupa skin. I 

 have never discovered such an organ, although 

 I am not prepared to say positively that it, or 

 something aualagous to it, does not exist. My 

 impression is, that it is not absolutely necessary. 

 The female is so exceedingly simple in her 

 structure, that fertilization is made possible by 

 the mere "overshadowing influence" of the 

 male, made at the only vulnerable point of con- 

 tact, which is through the T-shaped opening on 

 the thorax. I liave had the denuded females and 

 the males boxed up together, but there seemed 

 to be no recognition between them, but as soon 

 as I introduced the follicle of an unimpregnated 

 female, a male woiild discover it, and couple 

 with it almost immediately. 



I published a long paper, containing my ob- 

 servations on this insect, in the Penna. Farm 

 Journal in 1853 or 4, calling the attention of the 

 pcopliTto it, and suggested the simple remedy 

 you did. Some flve or six years afterwards it 

 was republished in the Fanner and Gardener, 

 and subsequently also in a weekly paper in this 

 city, but it appears to me that the people don't 

 read, or immediately forget what they read, for 

 some seasons the insect becomes still very de- 

 structive, and they "don't know what to do 

 about it." S. S. K.vtiivon. 



L.VXCASTER, Pa., Doe. 1, ISryj. 



THE HATEFUL, OR COLORADO GRA8SlIorPER. 



{Calopteiws fjin/us, Ulilcr :nKl Wal.sli ) 



C. V. RiLKV— i>e«r Sir: A summary of my 

 investigations in regard to the Hateful, or Itocky 

 Mountain Grasshopper (C'aloptenvs spretus'), 

 during my recent trip through Colorado and 

 New Mexico, may be interesting. But you are 

 aware that it takes several years to study 

 thoroughly the habits of any insect, especially 

 of one as widely distributed and variable in its 

 habits as this grasshopper. 



I will first give the /oc?« which came under 

 my own observation. ■ But to do this with any 

 degree of completeness, I shall fave to repeat a 

 portion of what is ah'eady written in my "Notes 

 on the Agriculture of Colorado." 



