182 THE ENTOMOLOGIST. 



sexual characters of the male. The last segment of the 

 abdomen is modified in the most extraordinary manner, re- 

 calling that of various Libellulae and Phrjganidse. Specimens 

 carefully mounted on card, as is the custom, are thus almost 

 impossible to determine. That the species known in this 

 country will be largely augmented, when a little attention 

 has been paid to them, does not admit of doubt. The male 

 characters are well figured by Kiesenwetter (Linn. Entom. 

 1852, vii. 265), but, from the difficulty of describing them, I 

 have borrowed the arrangement of Thomson, based on the 

 form of the thorax. 



A. Thorax subquadrate, distinctly margined at the sides. 



1. M. higuttatvs, L., Thorns. (Sk. Col. vi. 198). Mar- 

 ginata, Latr., Ksw. (i. D. 535). — One of our largest species. 

 Black ; thorax with the margins narrowly orange. Male 

 with very long antennae, and the head very broad. 



2. M. mi/siicus, Ksw. — Like biguttatus, but with the elytra 

 generally unicolorous, and the lateral margins of the thorax 

 dark. The male characters are very decided. Several spe- 

 cimens in Mr. Wollaston's collection. 



B. Thorax transverse, distinctly margined. Species small. 



M. hrevicollis, Pk., Thoms. {uec Kiesw.) Nigellus, Ksw. 

 — 1 line. A small entirely black species, with shining thorax. 

 I have two examples apparently referable to this species, but 

 unfortunately both are females, so that I cannot speak with 

 certainty. 



3. M. atomus, Thoms. Brevicollis, Ksw. (nee Payk.) — The 

 smallest species of the genus, easily known by its gray elytra, 

 the apices of which are faintly flavescent. Common, but 

 very difficult to preserve. 



C. Thorax with the sides immarginate j anterior angles 

 elevated. 



4. M.Jibulatus, Ksw. — A unicolorous species, but distinct 

 from M. mysticus by the antennae being pale at the base. The 

 male characters are also well marked. Several examples ap- 

 parently, from Cambridge, in Mr. Wollaston's collection, and 

 I have also seen a specimen from Dr. Power. 



