Miscellaneous. 147 



On the Developmental History and Reproductive Power of the 

 Orthoptera. By Vitus Gruber. 



In this memoir the Orthoptera are first of all divided into two 

 groups, in accordance with the different development of the wings in 

 their various stages : the insects belonging to the first section {For- 

 jiculince, Blattince, MantidcBt and Phasmidce) show in all their 

 stages more or less developed rudiments of wings liorizonally amal- 

 gamated with the mesonotum andmetanotum (horizontal-fixed-wing 

 development) ; those of the second group (including the Gryllidce, 

 LocustidcBy and Acridiidce)^ which are subjected to a more detailed 

 examination, in their first stages are either destitute of wing-rudi- 

 ments or have them united only vertically with the sides of the 

 meso- and metanotum (^Stadium lobulare i., ii., &c.), and in their 

 last phases of development possess distinct, free wing-sheaths placed 

 upon the back {Stadium vaginale i., ii., or idfimum, &c.). 



In the Gryllidce the first three stages (usually) present vertical- 

 attached wing-rudiments, the last two horizontal free wing-sheaths. 



The LocustidcB characterized by complete development of the 

 wings present a similar condition, whilst in the Acridiidce there 

 occur (probably) only two stages, with merely lobular lateral wing- 

 rudiments ; and the last two stages correspond with those of the 

 Gryllidae and Locustidce- 



The wing-sheaths in the last stage but one (vaginale i.) are more 

 separated from each other, reach in (most) Gryllidce only a little 

 beyond the metanotum, in the Acridiidce scarcely beyond the first, 

 and in the Locustidce not beyond the third dorsal plate, and never 

 show distinct transverse veins ; whilst in the last stage {vaginale ii.) 

 they accurately represent on a small scale the venation of the per- 

 fectly developed wings, and close together by their inner margins 

 over the middle line of the back hke a roof, the elytra being for the 

 most part concealed by the wing-sheaths. 



In those forms which, when fully developed, never possess wings, 

 and sometimes have only rudimentary elytra, the rudiments of the 

 flying-apparatus are proportionally smaller in the last stage and the 

 last but one; but in all cases distinct wing-sheaths are to be detected 

 besides the elytra {Platyphymay Pezotetticc, Chrysochroon $ , Tham- 

 notrizony &c.). 



Lastly, the author calls attention to the sexual differences of the 

 Locustidce and Acridiidce in their first stage, this being distinctly 

 expressed in the form of the last ventral (genital) plate. In tlie 

 male this is simple and more or less oval ; in the female, on the 

 contrary, composed either of four {Acridiidce) or six {Locustidce) 

 lamellae. From the comparison and dissection of the external sexual 

 apparatus of the female in the succeeding stages, it appears that the 

 ovipositor of a female Locustide is composed of six laminae (or more 

 properly three pairs of laminae), three of which unite to form a 

 lateral half. The previously quite unknown median lamellae are 

 very narrow, and setiform, and apply themselves very closely to the 

 inferior laminae. 



