184 PROCEEDINGS OF THE NATIONAL MUSEUM vol.85 



victim back of the head. Some of the ants tried to combat the 

 parasite by standing at an angle approximately 90° with the ground 

 and opening their mandibles in a threatening manner. The flies 

 were very alert and wary and the ants unable to cope with them. 

 Some of the ants that were struck by the fly stopped, bent their 

 heads downward, and with their front legs attempted to wipe the 

 back of their heads, others that were struck did not seem to be dis- 

 turbed in the least. All ants attacked kept on working or running 

 around and did not show any immediate ill effects. Apparently 

 a single fly can oviposit a large number of consecutive times (not on 

 the same ant). They hover over the ants and seek a propitious 

 time to strike. The fire ant Solenopsis xyloni when struck by the 

 phorid Apocephalus {Plastophoim) coquilletti Malloch will fall over 

 on its side or back, seemingly unable to coordinate leg movement, but 

 this is not true of the fungus ant so far as I have observed." 



Genus APOCEPHALUS Coquillett 



APOCEPHALUS COECUM, new species 



Figure 69, e-h 



Female. — Black, dull; frons (fig. 69, e) dull, nearly square, with 

 three strong frontal bristles on each side; just above the middle of 

 the front two large bristles, slightly anterior to and forming a trans- 

 verse row with the middle bristles; ocellar bristles large and forming 

 a straight transverse row with the upper bristles; postantennal bris- 

 tles as large as the f rontals, divergent and slightly reclinate. Antenna 

 (fig. 69, /) yellow ; third joint very large, somewhat elliptical, apical 

 end more pointed, with a brownish inf uscation ; arista a little longer 

 than antenna, first joint slightly longer than second, both tinged 

 with yellow, third joint black, with short pubescence. Palpus pale 

 yellow, with three or four black spiny bristles near the tip. Thorax 

 brownish on dorsum, pleura pale yellow^; mesopleuron bare; scutel- 

 lum darker, with two large bristles; halteres large, stems pale yel- 

 low, knobs black. Legs pale yellow, hind femur with a brown infus- 

 cation on both sides at the apex, all tarsi blackish. Abdomen with a 

 broad pale area down the middle of the dorsum, nearly white on 

 the first segment, luteous on segments 2 to 5 ; segments 2 to 5 broadly 

 white along apical edges, broadly black on their sides ; sixth segment 

 (fig. 69, h) black, with a very narrow white apical edge and ten large 

 bristles on the posterior margin (the six in the middle the strongest) ; 

 on the ventral side of the sixth segment a reddish-yellow projection, 

 with large black bristles arranged as in figure 69, li\ the apical or 

 genital segment sliiny black, with a slight tinge of yellow at the apex, 

 about one and one-half times as long as broad (the length appearing 



