330 CLAVICORNIA. [Atomaria. 



Thomson divides the genus as follows : 



Antrima- less distant from one another than from the eyes, 



with the fourth, sixth, and eighth joints less than those 



contiguous to them, and the first larger than the second ; 



body oblong, less convex, with the thorax not or scarcely 



transverse ATOMARIA, '. sp. 



Antennas more distant from one another than from eyes ; 



body short, with the thorax gibbous in front, transverse . AKOHICEBA, Thorns. 



The character, however, afforded by the relative distance of the 

 antennae from one another and from eyes is very unsatisfactory , and 

 practically useless, as any student will find who tries to separate species 

 by it ; it appears, therefore, to be the best course to abandon it 

 altogether, and to separate the species primarily by their general form, 

 which varies from the elongate shape of Cryptophagus to the almost 

 orbicular form of EpMstemm; for further particulars concerning the 

 genus the student is referred to Mr. T. Vernon Wollaston's excellent 

 revision, published in the Transactions of the Ent. Society of London, 

 vol. iv. N. S. part iii. 1857. 



The species may be divided for convenience sake into the following 

 three sections : 



I. Form elongate, parallel-sided, more or less depressed ; thorax not or only 



slightly transverse. 

 II. Form oblong, shorter, more or less parallel-sided, moderately depressed; thorax 



transverse, with posterior margin not raised in middle. 



III. Form short, more or less convex, sometimes ovate; thorax as a rule very 

 transverse but sometimes only moderately so, generally more or less gibbose in 

 front, with posterior margin more or less raised in middle. 



SECTION I. 



The species belonging to this section are distinguished by their 

 elongate, parallel, and generally subcylindrical form, which is however, 

 as a rule, somewhat depressed on the upper surface ; the greater part of 

 them are uncommon, but one or two (e.g. A. linearis) are occasionally 

 met with in such profusion as to have been recorded as injurious to 

 crops. 



I. Antennas with the last joint narrower than the 



penultimate ; size larger A. FIMBTARII, Herbst. 



II. Antennas with the last joint about as broad as 

 penultimate ; size smaller. 



i. Thorax as broad or nearly as broad at base as base 

 of elytra. 



1. Colour entirely yellowish -testaceous; posterior 

 angles of thorax right angles; antennae long and 



stout A. DILUTA, Er. 



2. Colour lighter or darker ferruginous, reddish- 

 brown, pitchy, or fuscous, apex of elytra usually 

 lighter than base ; posterior angles of thorax 

 blunt or romuk'd. 



