16 
Psyche 
[Vol. 93 
allowed eastward expansion by a whole complex of Sonoran Biota, 
from Opuntia, Cereus, Acacia and other xerophytes, to insects like 
Compsocryptus fasciipennis, several species of Joppidium, Lanugo 
retentor, Derocentrus longicaudis , Eiphosoma dentator (all Ich- 
neumonidae), Eumenes smithii (Eumenidae), Stictiella (Sphecidae) 
and even to vertebrates, such as the reptiles Crotalus, Sistrurus, Pit- 
uophis, Sceloporus, and Gopherus. 
Concurrently, similar physio-climatic events could have produced 
the plausibly vicariant differentiation of Compsocryptus fuscofasci- 
atus and C. melanostigma in South America. As discussed under C. 
melanostigma, the common ancestor of these two species may have 
ranged in Chaco vegetation from Argentina to coastal Peru at a 
time before the Andes were high enough at this latitude to impede 
east-west exchange of lowland biota. 
As intimated throughout the above discussion, Compsocryptus 
prefers semiarid or arid environments, but also may be abundant in 
open, degraded subtropical humid forests. Compsocryptus mela- 
nostigma, for example, has been cited from the very wet Selva 
Tucumano-Boliviana and Selva Misionera in Argentina. However, 
the majority of these forest records are from ecotones between forest 
and Chaco or from sites in the first stages of secondary succession 
(logging roads, clearings, windfalls, etc.). This fact demonstrates 
how precarious is the present-day equilibrium between forest and 
scrub (Selva and Chaco). Almost all modern forests are surrounded 
by drier environments, whose aggressive biota tends to encroach 
with the slightest ecological perturbation. Compsocryptus melano- 
stigma in Argentina and C. fasciipennis in south Florida are among 
the many indicator species of these often anthropogenic and usually 
disastrous environmental changes, from forest to scrub and finally 
to desert. 
Hosts 
Compsocryptus are among the most common, conspicuous, and 
frequently collected of New World Ichneumonidae. Nonetheless, 
practically nothing is known about their host relationships. Only 
Compsocryptus melanostigma has been reared. It parasitizes noc- 
tuid moths of the genera Alabama and Pseudaletia. Alabama larvae 
feed on cotton and pupate in rolled leaves. Pseudaletia larvae feed at 
night on many kinds of grains and grasses, hiding by day under 
