ABSTRACT The lacewing chrysopid species, Chrysemosa jeanneli (Navás, 1914) (Neuroptera: Chrysopidae) was recorded as a new species in Egypt. Specimens were identified and authenticated by the Natural History Museum (NHM) in London, UK. Laboratory studies were conducted at the Plant Protection Department, Faculty of Agriculture, Zagazig University, under controlled conditions (26 ± 1°C, 65 ± 5% RH) to evaluate the effects of three host plants (mango, navel orange, and mandarin trees) infested with Aphis gossypii (Glover) on the biological parameters of C. jeanneli. Results revealed that the shortest and longest total larval durations of C. jeanneli (14.36 ± 0.31 and 16.29 ± 0.29 days) occurred when larvae were reared on A. gossypii infesting mango and navel orange trees, respectively. The longest and shortest developmental periods were observed when larvae were reared on A. gossypii-infested mango (26.86 ± 0.36 days) and mandarin trees (25.00 ± 0.46 days). Total aphid consumption during the larval stage varied significantly among host plants, with larvae consuming 739.78 ± 16.03, 601.27 ± 4.15, and 370.14 ± 7.96 aphids on mango, navel orange, and mandarin trees, respectively. 142 J. Agric. & Env. Sci. (Damanhour University) 2025, 24(1): 142 - 162 Print: ISSN 1687-1464 Online: ISSN 2735-5098 Mean adult emergence rates were 92.86, 77.78, and 83.33 %, with sex ratios of 66.67, 57.14, and 62.00 % for mango, navel orange, and mandarin trees. The highest mean fecundity (390.63 ± 12.26 eggs) and longest female longevity (35.88 ± 1.03 days) were recorded for lacewings reared on A. gossypii from mango trees. Biochemical analysis indicated a direct relationship between the fecundity, fertility, and hatchability of C. jeanneli and the total protein and carbohydrate content of A. gossypii across host plants. Keywords: Chrysemosa jeanneli, newly recorded, Aphis gossypii, biological parameter, predation efficacy, biochemical analysis.