104? MODERN CLASSIFICATION OF INSECTS. 



by Striking violently with its hind legs upon the ground. The thorax 

 of the female of this species is stated by Messrs. Kirby and Spence 

 to have a transverse and hairy furrow {Introd. vol. iii. 305.) ; there is, 

 however, merely a triangular patch of hairs on each side, and several 

 small oblong pores, from whence the insect causes a milky fluid to 

 exude when captured. 



The genus Dyticus as now restricted, comprises the largest species 

 of the family, the colour of which is black tinged with olive, the 

 margins of the thorax and elytra being luteous. They are almost ex- 

 clusively European. Some of the species exhibit a very remarkable 

 anomaly, certain individuals having the elytra destitute of furrows, as 

 in the males, the anterior tarsi being, nevertheless, not patelliform. 

 Bonelli, however, ascertained by dissection, that these individuals 

 were females, and Ahrens took one of them paired with an ordinary 

 male. Mr. Stephens, accordingly, gave them as distinct species 

 under the names of conformis ? Kunze, and circumcinctus Ahrens 

 (^Stephens, vol. ii. pi. 12. f. 6.); and Mr. Kirby, who at first thought 

 these individuals might be neuters, raised them, subsequently, to 

 the rank of a genus under the name of Leionotus. Mr. Curtis, how- 

 ever, considers the latter species (which he misnames flavo-maculatus) 

 as a variety of the female of D. angustatus, and Ahrens described one 

 of these smooth-backed individuals as a " varietas problematica" of 

 the female of Dyticus marginalis, whilst Dr. Erichson considers that 

 there are three modifications in the character of the females in this 

 genus: — 1st, those differing from the males (D. latissimus, dimi- 

 diatus, &c.); 2d, those similar to the males (D. circumflexus, i^a^r.) ; 

 and 3d, those which are liable to variation, being either different or 

 similar to the males (D. marginalis Linn.^ and conformis Kunze, 

 D. circumcinctus Ahr., and dubius GylL, D. lapponicus Payk, and 

 septentrionalis GylL). An intermediate kind of individuals has also 

 been described by Erichson, in which the sulcations and punctures of 

 the elytra are obsolete ; and an apparently similar individual has also 

 been noticed by M. Guyot (A?mal. Soc. Ent. de France, 1 837. p. 1 6.). 

 In the neighbourhood of Berlin both kinds of females of D. cir- 

 cumcinctus are found promiscuously, elsewhere one or the other variety 

 is occasionally wanting ; thus in the lakes near Magdeburg, amongst 

 many thousands of Dyt. circumcinctus, not a single female with 

 sulcate elytra could be found. Gyllenhal indeed has described a closely 

 allied species (D. septentrionalis) as possessing simple anterior tarsi 



