THE PRACTICAL ENTOMOLOGIST. 



95 



EXPLANATION OF THE FIGURES. 



Fii^. 3 represents the embryo of a worm, a is the 

 iniudle tentacle of the head; e one of the posterior 

 tentacles; b the two eye-spots a 



at the base of the hinder pairl 

 of feelers; c is one of a row of 

 oar-like organs («V/-i) at the base 

 of which are inserted the locomo- 

 tive bristles, with the cirri serving 

 as swimming and locomotive or-| 

 gans ; d the caudal styles, or tail- 

 feelers. (From A. Agassiz). 



In this figure we see how slight 

 are the differences between the 

 feelers of the head, the oar-like 

 swimming organs, and the caudal! 

 filaments; we can easily see thatl 

 they are but modifications of a! 

 common form, and all arise from 

 the common limb-bearing region 

 of each ring of the body. 



The alimentary canal, with the 

 proventriculus, or anterior divi- 

 sion of the stomach, is seen to oc- Fig. 3. 

 cupy the middle of the body; while the mouth 

 opens on the under side of the head. 



Fig. 4 represents the young of the fresh-water 

 Lobster (Crawfish) before leaving the egg. The 

 body is divided into rings, ending 

 in lobes on the sides, which are thel 

 rudiments of the limbs, b is the! 

 rudiment of the eye-stalk, at the' 

 end of which is the eye; a is the 

 fore antennae; a' is the hind an- 

 tennae ; c is one of the maxilla- 

 feet; c' is the first pair of true feet 

 destined to form the huge "claw.', 

 (From Rathke). Thus the eye-! 

 stalk, antenna, claws and legs are Fi"-. 4. 

 moulded upnu a common form, and at first are scarce- 

 ly distiugui.^h.ible. Here we .sec the eujbryo divided 

 into a head. (hoi- 1\ ;iivl :i t.iil 



Fig. 5. A Case-fly. F!n;/rfnni'n, (after Zaddach), 

 in the egg, with part of the yolk (./;) not yet en- 

 closed within the body walls, a antenniB ; between 

 a and a' the mandibles; «' maxilla; ct- labium. 

 b. the separate eye-spots, (ocelli) which afterwar<ls 

 increase greatly in number and unite to form the 

 compound eye. The "neck" or junction of the 

 head with the thorax is seen at the front part of 

 the yolk mass; c the the three pairs of legs, which 



are folded once on themselves; d the pair of anal 

 legs attached to the tenth ring of the abdomen, as 

 seen in caterpillars, which form long antennae-like 

 filaments in the Cockroach and May-fly, etci The 

 rings of the body are but partially formed ; they 

 are cylindrical, giving the body a worm-like form. 

 Here as in the other two figures, though not so dis- 

 tinctly seen, the antennas, jaws and last pair of ab- 

 dominal legs are modifications of but a single form, 

 and grow out from the side of the body. The head- 

 appendages are directed forwards, as they are to be 

 adapted for sensory and feeding purposes; the legs 

 are directed downwards and they are to support 

 the insect while walking. It appears that the two 

 ends of the body are perfected before the middle, 

 and the under side before the upper, as we see the 

 yolk mass is not yet enclosed and the rings not yet 

 formed above. Thus all articulates differ from all 

 vertebrates in having the yolk mass situated on the 

 back, instead of on the belly as in the chick, dog, 

 or human embryo. A. s. p. 



"^ 



Chinch Bugs 



'* If any We.'itern rustics are verdant enough to suppose 

 that chinch bugs cannot be out-flanked, headed on and 

 conquered, they are entirely behind the times. The thing 

 has been effectually done during the past season, bj' Mr. 

 Davis, Supervisor of the town of Scott, Ogle county, Ills. 

 This gentleman had a cornfield of a hundred acres, grow- 

 ing alongside of an extensive field of small grain. The 

 bugs had finished up the latter and were preparing to at- 

 tack the former, when the owner, being of an ingenious 

 turn, hit upon a happy plan for circumventing them. He 

 surrounded the corn with a barrier of pine boards set up 

 edgewise, and partly buried in the ground, to keep therrl 

 in position. Outside of this fence deep holes were dug, 

 about ten feet apart. The upper edge of the board was 

 kejjt constantly moist with a coat of coal tar, which was 

 renewed every day. 



"The bugs, according to their regular tactics, advanc- 

 ed to the assault in solid columns, swarming by millions, 

 and hiding the ground. They easily ascended the boards, 

 but were unable to cross the belt of the coal tar. Some- 

 times they crowded upon one another, so as to bridge 

 over the barrier, but such places were immediately cov- 

 ered with a new coating. Tlie invaders were in a worse 

 quandary than that of ]3utler and Wuitzel at Fort Fisher, 

 and, in that state of mind, crept backward and forward 

 until they tumbled into the deep hole aforesaid. These 

 were soon filled, and the swarming myriads were shovel- 

 ed out of them literally by wagon loads, at tiie rate of 

 thirty or forty bushels a day — and buried up in other 

 holes, dug for the purpose, as required. This may seeni 

 incredible to persons unacquainted with this little pest, 

 but no one who has seen the countless myriads which 

 cover the earth as harvest approaches, will feel inclined 

 to dispute the statement. It is an unimpeachable fact. Thd 

 process was repeated till only three or four bushels could 

 be shovelled out of the holes, when it was abandoned, 

 The corn was completely protected, and yielded bounti- 

 fully." — {Prairie Farmer, copied in Valley Farmer, J un6 

 1, 1.S66, 



From what I have seen of the Chinch Bug, I 

 have no doubt that the above is substantially cor- 

 rect. B. D. w. 



The Practicai. ENTOvoi.m-.isT. — This able and highly 

 instructive journal commences in the May number a 

 series of articles designed as elementary le.ssons in the 

 science of Entomology, for the instruction of young per- 

 sons and others who may wish to acquire some knowledge 

 of this subject. It will prove a valuable feature and we 

 hope will excite a greater general interest and enlist a lar- 

 ger number of intelligent observers of the habits of in- 

 sects. Every farmer boy in the country should subscribe 

 for the Entomologist. Only 50 cts. a yeah — Sorgo Journal. 



