84 
Psyche 
[March 
30 of the 34 species collected. Only Traehysphyrus mesorufus 
(April), Joppidium rubriceps (April), Diapetimorpha sphenos 
(May, October, November), and Mallochia frontalis (September) 
were collected exclusively outside that period. Actually, December 
and January are the optimum months and yielded 273 specimens 
and 26 species, of which 23 species became most abundant at that 
time while three others overlapped into December or January from 
earlier or later maxima (Diapetimorpha macula peaks in Septem- 
ber, D. introita in March, and Acerastes pertinax in May and 
November). Finally, four species peak in late winter or early spring 
and/or fall but appear to avoid the early winter ( Cryptanura com- 
pacta in March, Mesostenus gracilis in March-May, M. longicaudis 
in March-May and August-September, and Diapetimorpha picta 
in March). Thus there is a large late fall and early winter fauna 
plus a much smaller exclusively late winter and early spring or 
spring-fall assemblage, but only minimal activity, and no exclusive 
species, during the hottest months of June, July, and August. This 
summer hiatus is demonstrated by the 1976 Malaise survey in 
Bentsen Park and by exhaustive hand collecting each year in late 
May and early June and again in the last week of August and the 
first 9 or 10 days of September. Moisture-loving ichneumonid 
adults avoid the extreme heat of subtropical summers and attain 
maximum abundance during the cooler months of the year, when 
they are less endangered by evaporative water loss and when there 
are many lepidopterous and coleopterous larvae and pupae to 
parasitize. 
As shown in Table 1, the Bentsen Park Malaise Trap collected 
a meagre sample of only 12 species and 138 specimens in all of 1976, 
and one characterized by mid-spring (April-May) and early fall 
(September-October) peaks of abundance with relatively few speci- 
mens captured in December-March and again in June-July. This 
result derives from the trap’s location in cool, humid woods under 
the deep shade of a large Pithecellobium. During winter, woodland 
mesostenines fly in sunny clearings and at the forest edge but, in 
warmer parts of the year they increasingly seek the protection of 
deep shade. 
Most Valley ichneumonids fly synchronously in climatically fa- 
vorable periods. My data do not suggest temporal differentiation 
of closely related species. This agrees with the general observation 
that ichneumonids, as parasitoids, mainly avoid competition by 
