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Except for eggs and first instars, the immature stages of Dasyhelea chani Wirth & Linley were more abundant on the lower than the upper surfaces of mature and mature old leaves of the water lettuce ( Pistia stratiotes L.). Eggs were laid close to the wet-dry line, usually just below it, and almost always on the upper leaf surface. First instars were closely associated with eggs. The remaining immatures were distributed mostly on the lower leaf surface, 0.5 cm or less below the wet-dry line. First and second instars usually were not farther than 2 cm below the line, whereas third and fourth instars were found over a wider range, sometimes as far as 4 cm below the line. Pupae occurred almost always on the lower leaf surface, on both sides of the line, and sometimes as far as 5 cm above it. P. stratiotes plants examined between July and August 1987 yielded an average of 2.3 egg batches (75.6 eggs), 2.6 second instars, 3.4 third instars, 5.8 fourth instars, 1.7 pupae, and 2.6 pupal skins per positive plant.

Eighteen species of Dasyhelea Kieffer are described and illustrated, of which 9 are new: brevicornis, brevicosta, leptobranchia, messcrsmithi, navaiac, pscudocincta, doincisurata, spinijorma , and stemlerae. D. subcaerulea Thomsen is synonymized with D. grisea (Coquillett) (NEW SYNONYMY). Species groups and subgeneric classification are discussed, and a key is given separation of the species.

Fourteen species of Ceratopogonidae were reared from cacti in California, Baja California, Arizona, and Texas. Thirteen are new to science: Forcipomyia desertensis, F. christiansoni, Dasyhelea cactorum, D. pentalineata, D. ryckmani, Cidicoides arizonensis, C. butleri, C. cacticolus, C. insolatus, C. jonesi, C. ryckmani, C. sitiens and C. torridus. The Culicoides species all belong to the Copiosus Group, which is reviewed with a diagnosis, discussion of distribution and habits, and a key to the 19 known species.

Two species of Forcipomyia , three of Dasyhelea , and eight of Culicoides are reported as reared from cacti in the southwestern United States and Baja California. These bred rather indiscriminately with respect to cactus host species; Dashyhelea cactorum is reported from three cactus genera ( Opuntia, Cereus , and Lophocereus ) while Culicoides ryckmani was reared from cacti of these same genera and also from Pachycereus. Decaying cacti apparently provide the major source of breeding material for ceratopogonids in many desert areas. The Copiosus group of Culicoides appear to have changed from treehole breeders to the cactiphilic habit in desert areas, and radiation occurred once the group became established in cacti. Insects and mites representing 34 other families were also reared from cacti in conjunction with the ceratopogonid research. A laboratory culture method used successfully with Drosophilidae, Neriidae, Ceratopogonidae, and Syrphidae employed boiled cactus tissues for larval development, while adults were fed a mixture of honey and protein hydrolysate.