468 N. E. McINDOO 
at the base. The number of pores on them is greatly reduced. 
The two remaining parasitic species, the fowl tick (44 Olfersia 
americana) and the ostrich tick (47 Hippobosca struthinionis), 
are winged and apparently are normal, unless one considers the 
number of their pores slightly reduced. 
TABLE 2 
Number of olfactory pores found on abnormal species 
NUMBER OF PORES ON Total 
NUMBER AND NAME OF SPECIES number of 
Legs Wings Halteres pores 
45’ Melophagus ovinugs 9. .....24-).5.5.8: 162 A EK 162 
48. Nycteribia bellardii o7............... 178 A F44 222 
Dimi @hione aval gaso kanes Gere prcleceer 391 B 28 419 
13. Pulicifora borinquensis @........... 168 C14 140 322 
46. Lipoptena depressa o’............... 144 D75 200 419 
44. Olfersia americana o..... Date wera 168 154 304 626 
47. Hippobosea struthinionis o’......... 180 167 442 789 
NES Tiere Yay Wao Arete EW (RP nek eae { a Ls Lu — 
391 167 442 789 
The following is an explanation of letters A to F in the above table: A, totally 
wingless; B, wing about as long as base of halter; C, wing about size of halter; 
D, wing much reduced, about same length as that of the short tarsus; HZ, halteres 
totally wanting; and F, halteres unusually small and peduncles threadlike. 
e. Generic, specific, individual, and sexual variations. As 
already stated, the variations between the olfactory pores of 
Hymenoptera, Coleoptera, Lepidoptera, and Diptera are large 
and in regard to both disposition and structure of the pores they 
are characteristic for each order. The variations among the 
families depend upon the families compared; for example, the 
disposition of the pores in Tipulidae and Muscidae is very differ- 
ent, but in Muscidae and Sarcophagidae only slightly different. 
The generic characteristics are slight variations in the disposition 
of the pores, while the specific variations are based almost solely 
upon the total number of pores present. The individual and 
sexual variations are distinguishable only by comparing the total 
number of pores present. 
A reference to tables 1 and 3 shows that the variations found 
pertain to the number of groups on the halteres and to the varia- 
tions in number of pores on the legs, wings, and halteres. Exclud- 
