REVISION OF STREPSIPTERA PIERCE. 



75 



Superfamily HALICTOPHAGOIDEA Pierce. 



1. Transverse slit narrow 2. 



Head sub truncate at apex, transverse slit very broad, cutting a deep three-sided 



emargination in the head igalliaphagus Pierce 



2. Mandibles prominent, toothed; thorax shorter than head, ventral slit turned pos- 



teriorly at sides Dioxocera Pierce. 



Mandibles mere lobes 3. 



3. Thorax shorter than head, rather suddenly narrowed to base; sides of head oblique. 



Pentoxocera Pien e. 

 Thorax longer than head, gradually narrowed to base; side of head convex. 



Megalechthrus Perkins . 



Superfamily ELENCHOIDEA Pierce. 



1. Head trilobed, mouth seemingly on an elevation; transverse slit narrow. 



Dcinelenchus Perkins. 



Head presenting two obsolete areas; transverse slit very broad, deeply cutting a 



rounded emargination into thorax; a thin curtain overhanging cavity at base. 



Mecynocera Pierce. 



An interesting and valuable comparison of genera may be had by 

 giving the range of variation in the following ratios. The first ratio 

 is that of the breadth at the spiracles (5) to the distance between the 

 mandibles (3); the second is that of the breadth of the head (4) to 

 the distance between the mandibles (3) ; the third is that of the breadth 

 at the spiracles (5) to the breadth of the head (4); the fourth is that 

 of the breadth of the spiracles (5) to the distance from spiracles to 

 apex (2). 



Genus. 



Dioxocera 



Crawfordia 



Vespaexenos 



Leionotoxenos 



Acroschismus 



Sceliphronechthrus . . 



Stylops 



Homilops 



Monobiaphila 



Halictoxenos typical 

 s. g. Halictophilus . . 



Cephalothorax. Head to 

 to mandibles. mandibles. 

 (5):(3)::-:l. (4):(3)::-:l. 



3.15 

 3. 14-4. 63 



4.12 

 4. 66-5. 11 

 4. 42-5. 90 



5.54 

 6. 06-8. 11 



6. 26-8. 30 



6.93 

 6. 66-9. 71 



7. 81-8. 00 



3.15 

 2. 96-4 47 



3.50 

 4. 00-4. 90 

 3. 36-4. 08 



4.18 

 3. 46-5. 64 

 5. 12-6. 00 



4.40 

 3. 16-5. 00 

 5. 45-5. 70 



Cephalothorax 

 to head. 



(5):(4)::-:l. 



1.00 

 1. 03-1. 06 



1.17 

 1. 03-1. 16 

 1. 22-1. 46 



1.32 

 1. 36-1. 88 

 1. 14-1. 41 



1.60 

 1. 90-2. 10 

 1. 40-1. 43 



Breadth 

 to length. 



(5):(2):':-:l. 



1.40 

 1. 41-1. 70 



1.04 



1.33-1.64 



1. 31-2. 43(?) 



1.84 

 1. 32-1. 77 

 1.74-1.95 



1.76 

 1. 29-1. 55 

 1. 32-1. 33 



Table for separation of genera of the Triungulinids. 



Nine abdominal segments simple, the tenth consisting of two large lateral lobes, 



each bearing a long stylet Stylops, Halictoxenos. 



Eight abdominal segments simple, ninth elongate inclosing tenth 2. 



Ninth laterally armed with stylets, and tenth apically so Mecynocera. 



Tenth only, terminated by two large approximate lobes bearing stylets. 



Acroschismus, Vespaexenos, Monobiaphila, Leionotoxenos, Ophthahnnchlus, 



Homilops, and Pentoxocera. 



