Ll. Lloyd 5 



On the younger foliage of tlie tuberous begonias none of the scales 

 survived the first moult and on the older leaves scales at the extreme 

 periphery alone reached maturity. A similar thing occurred on fuchsias 

 of the Mrs Marshall type where frequently a leaf was found with a 

 complete fringe of mature or empty scales while on the rest of the leaf 

 all the scales were dead. On chrysanthemums breeding was free on old 

 foliage but not common on young growth. On two weeds strongly 

 favoured by the adults, Solanum dulcamara and Lamiuni purpureum, 

 no scale was ever found to mature, all dying either before or just after 

 the first moult. On narcissus, tulip, hyacinth and various grasses eggs 

 were often laid, but no larvae passed the first moult. Mature scales have 

 been found rarely on elder and hawthorn and rather frequently on elm. 

 This list by no means exhausts the food plants of the insect which were 

 noted, but is merely indicative of its range. 



4. HABITS OF ADULTS. 



The adults usually mate on the leaf on which they emerge and 

 frequently commence oviposition there. Later they seek younger foliage. 

 Outside, when there is a perceptible wind, they are very reluctant to 

 take flight, but on warm still days they may sometimes be seen hovering 

 in numbers over their host plant. In the tomato houses they often remain 

 very localised until the infestation on a few plants has become massive. 

 Trimming the plants and the consequent disturbance aids their dispersal. 

 They are distinctly gregarious as the following figures show, the counts 

 being made in each case on foliage on which no adults had emerged. 



On July 8, large bushy S. dulcamara growing under staging in the 

 greenhouse, 260 leaflets all young and tender, plant held 90 flies dis- 

 tributed on 35 leaflets and of these 15 (16*6 per cent.) were on one 

 leaflet and 9 (10 per cent.) on another. 



On July 16, 10 plants, Trifolium sativum, growing in a box in the 

 greenhouse held 242 flies distributed as follows: 7, 4, 35, 79 (33 per cent.), 

 16, 11, 3, 0, 53, 34. 



On July 20 the top 40 leaves of an Al. rosea held 129 flies of which 

 55 (43 per cent.) were on the 22nd leaf from the top. 



On August 27, a young Urtica held 32 flies of which 22 (68 per cent.) 

 were on one leaf and the others distributed over the remaining 11 leaves. 



This gregarious habit has possibly originated for the better protection 

 of the scales from parasites. If a healthy scale is watched under a 

 moderately high power of the microscope and in bright sunlight, the 

 '"honey dew"' excreted at the anus in the base of the lingula is seen to 



