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Investigation on, "Diversity and predation potential of major aphidophagous predators in maize" was carried out at the Instructional Farm, Rajasthan College of Agriculture, Udaipur during summer (April to July, 2013) and monsoon (July to October, 2013) seasons with the objectives to study the diversity of aphids feeding natural enemies and evaluate the predation potential of major insect groups of the aphidophagous guild in the field and laboratory. The aphid pest recorded on maize was Rhopalosiphum maidis (Fitch). Among the aphidophagous predatory guild, the major insect groups included coccinellids (Coccinella septempunctata Linnaeus, Cheilomenes sexmaculatus (Fabricius) and Brumoides suturalis (Fabricius): Coccinellidae, Coleoptera); lygaeid bug (Geocoris sp.: Lygaeidae, Hemiptera,); rove beetle [Paederus fuscipes Curtis: Staphylindae, Coleoptera] and syrphid flies (Ischiodon sp.: Syrphidae, Diptera; being dominant). The seasonal mean population of aphids was higher during monsoon season crop (369.09/plant) than during the summer season (291.26/plant). Likewise, the seasonal mean population of the aphidophagous predators per plant was relatively more during monsoon season being 8.56 (coccinellids), 3.76 (Geocoris sp.), 3.14 (P. fuscipes) and 2.41 (syrphid flies); whereas, in summer season the corresponding values were 7.78 (coccinellids), 3.60 (Geocoris sp.), 2.87 (P. fuscipes) and 1.89 (syrphid flies). Exclusion of the ground dwelling aphidophagous predators resulted into significantly more aphid predation (99.75%) than when aerial aphidophagous predators were excluded from access to aphid prey (89.38%). In the no exclusion treatment, where both types of predators (aerial and ground dwelling) had equal access to aphid prey, the decrease in aphid numbers was the maximum (100%). The coccinellid grubs and adult beetles consumed relatively more aphids at lower aphid densities (25, 50 and 75), significantly being the maximum at a prey density of 75. At higher aphid densities (100, 125 and 150) the consumption rates declined. The feeding behaviour of coccinellids showed a sharp decline in percentage feeding with an increase in prey density for both adults and grubs.

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The present paper describes two new species of Conocephalus: Conocephalus decaspinosus sp. nov. and C. kwasiphaiensis sp. nov., as additions to the previously known species of the genus; among these, two species have been reported for the first time from India, viz., C. concolor peneri and C. vaginalis. The key morphological characters of the head, pronotum, cerci, spines on the fore tibiae, hind femora, stridulatory file and the ovipositor have been illustrated with suitable line drawings to distinguish the reported new species. The distribution map of the species in India has been provided with a key to the subgenera.