The biology of this malacophagous belostomatid Limnogeton lie‌bort was studied under four different degrees of water temperature: 20,25,30 and 35.C. in association with feeding upon 13lomphataria alez‌andrina snails, the Intermediate host of Schistosoma mansoni Sambon, in Egypt. At the aforementioned thermal conditions, the total nymphal peri‌ods lasted, 102.0916.33, 62.3513.63, 3631.8 and 26±1.76 days, re‌spectively, showing significant differences. Consequently, respective nymphal mortalities of 45. 7.5, 37.5 and 70% were recorded and showed highly significant differences. Under these conditions 183.95417.79, 166.81310.5. 142.22318.28 and 162.7539.98 Individ‌uals of Balexandrina wore consumed with daily rates of 1.81±0.20, 2.710.22. 3.9530.39 and 6.27±0.20 indviduals. respectively. On the other hand, respective sex ratioes (female: male) of 1.75:1,1.18:1,1.1:1 and 1:2 were recorded. The number of egg rafts laid per female were 2.57±0.53, 7.41* 1.12, 5.83±1.59 and 3.67±0.58, giving total of 90.43117.21, 509.94±58.51, 387.25366.38 and 289.87110.21, eggs / female, re-spectively. The consumption by adults Increased with the increase of temperature from 20 to35cC. The longevity of females and males in association with the afore. mentioned thermal conditions were 443.50173.88 and 403.5132.19 days; 400.9t56.19 and 419.9168.55 days; 161.3±30.76 and 258.25±74.23 days; 92.25±24.17 and 195.0314.48 days, respectively. Thus, males lived significantly longer life span than females. Incubation periods of eggs were 21.25±2.06: 17.74±0.63: 10.9710.83 and 9.510.5 days, respectively. Consequently, hatchability per cent reached 62.518.52; 91.84±7.63; 83.1±7.91 and 81.7817.52%, respectively.