ART. 17. LARVAE OF HOLARCTIO TIGER-BEETLES HAMILTON. 59 



the inner hooks and mesad of the distal half of the median hooks 

 arranged transversely. 



Measurements. — Length of larva, 28 to 30 mm., width at the third 

 abdominal segment, 3.5 to 4 mm.; diameter of ocellus 2, 0.65 mm.; 

 distance between ocelli 1 and 2, 0.45 mm.; length of fronto-clypeo- 

 labral area, 3.3 mm.; width, 3 mm.; length of pronotum, 3.8 mm.; 

 width, 4.9 mm. 



This larva is an European form and can be distinguished from the 

 American species by the absence of the pearly white color on the 

 lateral and caudal margins of the pronotum, by the greater propor- 

 tional diameter of ocellus 2 to the distance between ocelli 1 and 2, 

 and by the two prominent setae on the median hooks. 



TETRACHA CAROLINA Linnaeus. 



Figs. 2, 9, 15, 18, 24, 29, 34, 43, 80, and 116. 



Shelfobd, reared, larvae in collection at University of Illinois, the U. S. 

 National Museum, and author's collection. 



Color. — Head and pronotum dark purple with a green reflection, 

 lateral and caudal margins of pronotum pearly white; setae brown, 

 some of those on the head and pronotum occasionally white. 



Head. — Setae on dorsal aspect long, slightly flattened, and promi- 

 nent; diameter of ocellus 2 slightly greater than the distance between 

 ocelli 1 and 2; fronto-clypeo-labral area longer than wide; trans- 

 verse ridge on caudal part of frons with three setae; antenna with 

 the proximal segment slightly longer than the second, the third 

 slightly more than one-half, and the distal slightly less than one- 

 half the length of the second, setae long and stout, the proximal seg- 

 ment with nine to eleven setae and the second with eleven to thirteen ; 

 maxilla with the proximal segment of the galea bearing four setae on 

 its mesal margin; ligula with four fine setae at its ventro-distal end 

 not in a transverse row, the two mesal setae caudad of the lateral 

 ones, proximal segment of the labial palpus with six or seven setae, 

 the distal segment with one. 



Thorax. — Pronotum with the cephalo-lateral angles extending 

 cephalad of the mesal portion, lateral margins slightly carinate, pri- 

 mary setae large and prominent, secondary setae small and not nu- 

 merous (fig. 80). 



Ahdomen. — Chitinized areas distinct, secondary setae short, fine, 

 not numerous, few occurring between the chitinized areas (fig. 116) ; 

 median hooks with a single prominent setae ; inner hooks about one- 

 half the length of the median hooks and with two fine, inconspicuous 

 setae ; three prominent setae cephalad of the mesal hooks and mesad 

 of the distal half of the inner hooks usually forming a longitudinal 

 row. 



