A REVISION OF THE GENUS LOCUSTA, L. 



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cerci (fig. 8, A) rather large, compressed laterally ; subgenital plate with 

 the apex slightly widened ; penis (fig. 8, B) very short, with short acute 

 apex. $ (fig. 8, E) : subgenital plate with lateral margins slightly convex ; 

 apex rounded, with a median projection and bisinuate laterally ; lower 

 valves of ovipositor with the basal part about as long as broad, the apical 

 part unarmed laterally . . . . . . . . . . Locustana, g. n. 



Genotype : Pachytylus pardalinus. Walk. 



This key shows only the most striking differences between the two genera ; other 

 distinctive characters, especially those observed in the male genitalia, may be easily 

 understood by a comparison of the figures (figs. 7 and 8). 



Fig. 8. Genitalia of Locustana pavdalina. Walk. : A, male supra-anal plate and cerci from above ; 



B, penis and lower genital valves {e) in profile ; C, epiphallus ; D, upper bridge of genital valves ; 



E, end of female abdomen from beneath. (E x 3, remainder x 12). 



A full description of the new genus Locustana is given below. 



Key to the Phases of Locusta migratoria, L.* (figs. 1 & 4). 



1 (2) Pronotum distinctly compressed laterally, but feebly constricted before the 



middle ; median keel high, tectiform, convex in profile ; the fore margin 

 angulately prominent ; the hind angle acute. Hind femora (on the average) 

 longer than half the elytra. Hind tibiae often red. Larvae of variable 

 coloration, but never black and red (or black and yellow). Both larvae 

 and adults occur singly or in very loose swarms . . . . ph. danica, L. 



2 (1) Pronotum only feebly compressed laterally, but distinctly constricted before the 



middle ; median keel low, neither tectiform, nor convex in profile ; fore 

 margin not prominent ; hind angle not acute. Hind femora (on the average) 

 shorter than half the elytra. Hind tibiae only exceptionally red. Larvae 

 of a constant black and red (or black and yellow) coloration. Both larvae 

 and adults occur in dense swarms. 



* It is quite obvious that the exact determination of the phases is possible only in the case of 

 typical specimens and not of intermediate examples ; the most reliable results can be obtained 

 only from examination of large series. 



