22- 



The pre-anal lamina or super-anal plate is the triangular piece which in 

 both sexes lies over the anal aperture. 



The ovipositor (Fig. 1, ov) of the female consists of four corneous pieces, 

 two of which curve upward and two downward, usually called the valves; 

 but Lacaze-Duthiers, who has made the genital organs a special study, applies 

 different names to the separate pairs, thus : the upper pair are his ejiisternitcs , 

 because they are above the little central piece, which he considers the repre- 

 sentative of the ninth sternite; the lower pair are his tergo-rJiabditcs* 



Dr. Packardf says, "The ovipositor, with its accessory pieces, consists of 

 a sub-genital plate formed by the seventh sternite ; the ninth segment is com- 

 plete, and the blades (tergo-rhabdites), composing the ovipositor, consist of 

 three secondary pieces united together between them.'' 



INTERNAL STRUCTURE. 



It is impossible to convey a correct idea of the internal structure with- 

 out the aid of figures, which I am unable to give in the present work ; and, 

 moreover, I have nothing to add to what has already been published by 

 Marcel de Serres, Burmeister, Lcion Dufour, Siebold, Lacaze-Duthiers, and 

 others, yet the following general statements may be of some interest to the 

 young entomologist into whose hands this work may fall. 



The nervous system, according to L^on Dufour,J consists of a double 

 nervous chord, extending from the head to the tip of the abdomen along the 

 lower part of the body, expanding at various points into ganglia, which emit 

 a greater or less number of branches to the right and left. These ganglia 

 are classed in three groups, according to the part of the body in which 

 they are situated — cejjhalic, thoracic, and abdominal. The cephalic ganglion 

 is the largest of the number, and is deeply emarginate in front, giving it the 

 appearance of being somewhat bilobed ; in Tryxalis this feature appears to 

 be most strongly marked. In each of the thoracic divisions there is a gan- 

 glion, that of the metathorax presenting the largest number of branches. The 

 abdominal ganglia, of which there are some six or seven, are all small except 

 the last, which is next in size to that of the head, emitting to each side three 

 important branches, connected, doubtless, with the generative organs. This 



* Why he calls these tergo-rJiabdites, when they are below the steruito, I do not 

 understand (see his Plate XII, Fig. 2, i). 

 t Guide to Study Ins., 567. 

 fReeherches sur les orthopt^res, &c., Inst, de Prance, torn. 17, 1841. 



