148 



BULLETIN 66, UNITED STATES NATIONAL MUSEUM. 



obtained which is very different from that of saiy other genus. The 

 measurements are with a Zeiss stand, 160 tube, 2 eyepiece, and A 

 objective; 1 space = 0.0076 mm. 



Species. 



manilx. . . 



robbii 



crawfordi. 

 grxnichcri 

 zephyri... 

 versati 



Length. 



Spiracles 

 to apex. 



Breadth 

 between 

 mandi- 

 bles. 



Breadth 



of 



head. 



Breadth 



at 

 spiracles. 



Greatest 

 breadth. 



From these figures the following ratios, which are derived as in the 

 discussion of Stylops, are obtained: 



Species. 



manilx 



robbii 



craicfordi . . 

 grxnichcri. 



zephyri 



versati 



sparsi 



Cephalothorax Head to man- 



to mandibles. 

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



7.81 

 8.00 

 6.66 

 7. GO 

 8.22 

 9.71 

 8.75 



dibles. 

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



5.45 

 5.70 

 3.16 

 4.00 

 3.55 

 5.00 

 4.28 



Cephalothorax 

 to head. 



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



1.43 



1.40 

 2.10 

 1.90 

 2.31 

 1.94 

 2.06 



Breadth to 

 length. 



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



1.32 

 1.33 

 1.29 

 1.33 

 1.34 

 1.36 

 1.55 



The great difference in shape between the two Philippine species 

 and the American specimens led to the division of this genus into 

 two subgenera. 



Subgenus HaMctoxenos is parasitic on Chloralictus, a subgenus of 

 green JIalictus, and is typically American. The breadth of the 

 cephalothorax is 1.9 to 2.3 times the breadth of the base of the head, 

 and the breadth of the head is 3.1 to 5 times the distance between 

 the mandibles. 



Subgenus HalictopMlus is parasitic on Evylseus, a subgenus of 

 black Halictus, and is typically Philippine. The breadth of the 

 cephalothorax is 1.4 times the breadth of the base of the head, and 

 the breadth of the head is 5.4 to 5.7 times the distance between the 

 mandibles. 



There is very little doubt that when males are found these sub- 

 genera will become genera, and that Halictostylops of Europe, which 

 is founded on a parasite of a black Halictus, will fall near Halictoph- 

 ilus of the Philippines and out of the Stylopidse, where it is now pro- 

 visionally placed. 



