304 KEPORT OF THE COMMISSIONER OF AGRICULTURE. 



stems bot and allowed it to cool. I set one can on each hill and placed 

 therein a woolen string (in thickness about the size of a wheat straw), 

 thoroughly wet it, and allowed it to hang to the plants. The string 

 acts as a siphon, and draws the liquid out drop by drop, and keeps the 

 plant continually moistened with the offensive liquid, thus driving all 

 insects away. It further assists in the growth of the plants by keeping 

 the roots moist, yet so continual and gradual is the application that the 

 sun neither scalds nor bakes the earth. I merely mention this, as it 

 may be something new, and I assure you it is worthy of a trial, as it 

 proved entirely satisfactory to me this season. 



DESCRIPTIVE. 



Phyllotreta vittata.— Larva.— Length, 5 mm ; width, 0.7 mm . A long, slender, 

 subcyliudrical larva, tapering but slightly at either end. The general color is yellow- 

 ish-white ; head dark brown, mandibles still darker, and labium light brown. The 

 dorsum of every abdominal joint, except the last, is marked with two nearly trans- 

 verse rows of about ten very small, dark, piliferous warts, the rows separating near 

 the dorsal line and approximating laterally. The legs are well developed, and the 

 coxa of each has an irregular dark-brown, chitinous ring, which sends a short pro- 

 longation down the anterior portion of each femur. The tarsi each support an ob- 

 conical pulvillus, but no claws. The base of this pulvillus presents the appearance 

 of a sucking disk. 



The general surface of the body is microscopically granulate. The prothoracic 

 plate is not well marked, and is of a broad, irregular, hexagonal shape. The anal 

 plate is heavy, brown in color, and occupies the whole of the dorsum of the anal joint. 

 Its lateral edges bear eight stout hairs, and upon its dorsal surface are eight more, 

 one transverse row of four near the middle of the joint, a transverse row of two im- 

 mediately behind this, and one near each anterior corner. The aotennce are very short 

 and stout, and 2-jointed. The maxillary palpi are large, conical, and apparently 3- 

 jointed, differing from those of the European nemorum in that the first joint is long 

 and stout, while the second joint is insignificant; in nemorum the second is very promi- 

 nent. Labial palpi very short, 2-jointed. The mandibles are stout and 4-dentate; 

 the first two teeth are large and sharp, the third smaller, and the fourth small and 

 rounded. Th^ maxillae are conical, and each bears a tuft of stout bristles. The 

 labrum is prominent, and its front border forms at tip approximately an arc of a circle; 

 it is rugose at its anterior border, but not subdentate, as with nemorum. The chitinous 

 patches, so strong over the integument of zimmermanni, are but faintly indicated here. 



ZIMMEBMANN'S FLEA-BEETLE. 

 (Phyllotreta zimmermanm. Crotch.) 

 Order Coleopteba ; Family Ohrysomelidje. 

 [Plate IV; Fig. 1.] 



This little beetle (Plate IV, Fig. 1, d) much resembles the preceding 

 species (Ph. vittata), and as it is also found upon cabbage and other 

 cruciferous plants, although seldom if ever in such numbers as the other, 

 the two species are without doubt often confounded. The larvae, too, 

 are quite similar, but differ widely in habit. Instead of feeding upon 

 the roots, that of zimmermanni mines the leaves of certain cruciferous 

 plants, and notably the wild Pepper-grass (Lepidium virginicum). While 

 the habits of the former have been long since known, those of the latter 

 have not hitherto been published. We first bred it from Lepidium in 

 1872 at Saint Louis, and the following account is taken from our notes 

 of that time, and from more recent observations made at our request by 

 Miss M. E. Murtfeldt, at Kirkwood, Mo. 



The wild Pepper-grass upon which the insect is found is one of the 

 most common and abundant weeds in that locality, and, during the 



