DIABEOTICA. 513 



very short and triangular-shaped third joint of the antennae ; in the differently 

 shaped elytra! bands, these bands being greatly constricted near the suture but strongly 

 widened at the sides ; and in the angular third band not quite extending to the 

 suture. 



25. Diabrotica circulata. (Tab. xxix. fig. 5.) 



Diabrotica circulata, Harold, Coleopt. Hefte, xiii. p. 91 (1875) \ 



Hab. Mexico, Tuxtla (SallS); Guatemala 1 , Pantaleon, Zapote, Duenas, Capetillo, 

 San Geronimo, Purula, San Joaquin, Chacoj (Champion). — Colombia (coll. Baly). 



This species seems to be so extremely variable in the markings of the elytra that I 

 find it quite impossible to fix any limit or come to any certain conclusion regarding it. 

 Von Harold has given only short diagnoses of I), biannularis and D. circulata ; the last- 

 named he separates by the bifoveolate thorax, the more oblong shape of the bluish 

 elytral rings, and the more strongly punctured elytral surface. All these characters 

 seem to lose their value amongst the large amount of material now before me, in which 

 specimens from one and the same locality vary in having either an obscurely depressed, 

 bifoveolate, or trifoveolate thorax, and the antennae unicolorous fulvous, or with the 

 intermediate joints darkened; and in regard to the elytral ring-shaped markings, the 

 same amount of variation may be seen, the rings being either narrow or broad, open or 

 closed, and it would be easy to make half a dozen new species (?) on these variable 

 characters. I will, however, refer at present the Guatemalan specimens with thick and 

 strongly-marked blue rings, of which the posterior one is rather angular and open, to 

 D. circulata. We figure an example of this kind from Pantaleon. 



26. Diabrotica biannularis. (Tab. XXIX. fig. 7.) 



Diabrotica biannularis, Harold, Coleopt. Hefte, xiii. p. 91 (1875) 1 ; Klug, Dej. Cat. 3rd ed. p. 404 2 . 

 Diabrotica oculata, Sturm, in litt. 



Sab. Mexico x 2 , Vera Cruz, Toxpam, Cordova, Tuxtla (Salle), Jalapa, Tapachula 

 in Chiapas (Edge) ; Beitish Hondueas, R. Sarstoon (Blancaneaux) ; Hondueas 

 (Salle). 



D. biannularis resembles greatly in the elytral pattern certain forms of D. nummu- 

 laris, but differs in the flavous or pale fulvous thorax, this latter being less convex, and 

 having three more or less distinct fovese. The antennae have the intermediate joints, 

 and often the apical one also, fuscous, and are altogether more slender and elongate. 

 The colour of the head seems, however, subject to variation, and the ring-shaped 

 marks of the elytra are as often closed as open. An example from Vera Cruz is 

 figured. 



biol. centr.-amee., Coleopt , Vol. VI. Pt. 1, June 1887. 3 u 



