Miscellaneous. 681 



lying upon a very thin basement membrane. The epithelium is 

 formed of a number of excretory cells, varying with the species, and 

 encloses a very fine central lumen. 



Among the various excretory products of these glands I have 

 found abundance of sodic and calcic urate in Gri/Uas ; uric acid in 

 Grifllotalpa in the form of irregular spherical or ovoid concretions 

 and prismatic crystals ; sodic urate and uric acid in Blitta and 

 PeripJaneta. 



The research has been made on about eighty species, belonging 

 to seven principal families of the Orthoptera, and I will now 

 proceed to describe the results, insisting specially on the mode of 

 opening of the Malpighian tubes. Further, thanks to the numerous 

 specimens placed at our disposal, I have been enabled to observe 

 the diverse modes of opening which the urinary organs affect in 

 Orthoptera, and to follow out all the phases between the two ex- 

 treme types — that is to say, those in which the tubes of ilalpighi 

 open into the end of the intestine at the summit of a number of 

 tubercles grouped in circles, and those in which they form only one 

 large bundle, opening at the end into a long urethral tube dilated 

 at the extremity. 



We win pass in review the several families in the order of 

 diminution of complication. 



The tubes of Malpighi in the Forficulidae are small in number 

 ("8 to 10) and grouped in two bundles placed at the ends of a 

 diameter at the origin of the terminal intestine. 



In the Phasmidfe the urinary organs are very numerous and 

 united in several bundles (20 to 24 in Fhibalosoma), opening into an 

 equal number of hemispherical or conical tubercles, very short and 

 disposed in a circle around the intestine, of which they are nothing 

 more than simple evaginations. In Acanthodenis and Xecroscia 

 each collecting-tubercle receives but two or three Malpighian tubes. 



The Mantidie possess 60 to 70 urinary tubes, inserted sometimes 

 irregularly, sometimes grouped in bundles (3 or 4) at the origin of 

 the terminal mtesXme { EremiaphiJa). The Praying Mantis possesses 

 50 or 60, united in several bundles separated by narrow free spaces. 



In Periplaneta and Blatta the Malpighian tubes are grouped in 

 6 bundles, each comprising 1.5 to 20 tubes opening on the summit 

 of a very short conical tubercle. Tliese six tubercles, greatly re- 

 duced and with a broad base, arise from intestinal evaginations. 

 They are about equidistant from one another and arranged in a 

 circle around the intestine. The urinary orjjans of Poli/zosterm are 

 thin, short, winding, and arranged equally in six groups. In 

 Blahera the mode of opening of the tubes of Malpighi is altogether 

 characteristic and quite different from that observed in other Blattida;. 

 The tubular glands, to the number of .50 or 60, open on an irregular 

 area comprising about one third of the circumference of the in- 

 testine. 



In the family of the Acridiidse the number of Malpighian tubes 

 is very variable, certain species (Pcecilocerus, Pyrriomorpha) having 

 as many as 100; others have 60 to 70 (Pampha<ji(^), and some 70 

 to 80 "((Edipoda) or 50 to 60 (Psophm, Pachyti/lns, &c.). In all 



Ann. (t' Mag. X. Hist. Ser. H. Vol. xix. 47 



