96 DESCRIPTION OF INSECTS 



Dytiscus fenestralis. Melsh. Calal. 



Bodij black, above slightly bronzed and divided into very mi- 

 nute, suborbicular, depressed granules, beneath piceous- 

 black. 

 Head with two obsolete piceous spots on the vertex, a de- 

 finite, impressed, abbreviated, oblique, frontal line, with a 

 smaller oblique one above, each side ; antennee and palpi 

 piceous. 

 Thorax, an obsolete, punctiform, central line, often wanting. 

 Elytra, on each a submarginal, elongated, obsolete, rufous 

 spot behind the middle, and a subtriangular one near the 

 tip. 

 Pectus and postpedus not obviously granulated ; sternum 

 acutely carinated ; feet piceous ; vetiter with very nu- 

 merous, oblique, irregular lines. 

 Far. a. Above dark reddisli-brown, margin paler, spots yel- 

 low, distinct, beneath piceous ; feet pale rufous. 

 My friend Dr. J. F. Melsheimer, in a letter written some- 

 time since, observes that " the two yellowish macula near 

 the apex of the elytra differ oftentimes in de[)tii of colouring 

 and in size. I have several specimens that have the macula 

 of an irregular, others of an oval or elongated form, and the 

 colour of all the different shades from a faint yellow to a 

 light brown. It delights in miry forest springs, where it 

 feeds on tender vegetables and minute insects. If it is 

 caught and pressed between the fingers, it will exudate from 

 the divisional line of the stethidium {truncus) and abdomen, 

 a white milky substance. It moves with great activity." 



It undoubtedly approaches very closely to C. fenestratus 

 of Europe, which insect has the same fenestrate elytral 

 spots ; as well as another insect, which is described by Mar- 

 sham under the name of D. obscurus. 



3. C. *ambiguus black ; elytra dark reddish-brown ; feet 

 rufous; body somewhat acute behind; vertex with obsolete 

 piceous spots. 



