C. B. Williams 229 



Pairing takes place in the manner usually found in this group. It 

 has been described and figured by Buffa (1907, p. 18) for Aeolothrips 

 fasciata. The male climbs on the back of the female with its front legs 

 on the thorax of the latter and the end of its abdomen curled under- 

 neath that of the female. 



Parthenogenesis. Although the males are quite common early in 

 the year and pairing has been observed to take place, yet the eggs are 

 quite capable of developing parthcnogenetically ; eggs laid by a female 

 bred in captivity and known not to have paired developed in the normal 

 manner. In many other species of Thysanoptera parthenogenesis is 

 quite normal, in some the male being still unknown. 



The adults do not readily take to flight and when they are forced to 

 do so it is usually only for a very short distance. I have no evidence 

 as to whether they are capable of long sustained flight and migration, 

 such as is the case with the corn thrips {Limothrips cerealium). 



The food of the adults consists, like that of the larvae, of the juices 

 of the plant, which are taken in by a piercing and rasping action of the 

 three stylets in the mouth. They usually confine themselves to the 

 soft tissue inside the flower and also suck the pollen. 



The actual act of oviposition has not been observed in this species, 

 but in a closely allied species Taeniofhrips primulae, which lays more 

 openly in the leaves and flower-stalks of the primrose {Primula vulgaris), 

 it seems likely that the egg flows gradually into the slit made by the 

 ovipositor similar to the method recently described for a sawfiy by 

 Chapman {Trans. Enf. Soc. Lond., 1914, p. 173). Although the egg 

 is very large compared with the size of the insect, it could not be seen 

 to pass in bulk into the prepared slit. 



The Egg (Figs. 3, 4 and 5). 



The egg is, as is typical for this family, soft, opaque white and more 

 or less bean-shaped but varies slightly in contour, sometimes the head 

 end being more projecting (Fig. 3). It is 0-35 mm. long X 0-25 mm. 

 broad and is large compared with the size of the parent. It is 

 laid embedded in the tissue of the plant, in a slit made by the 

 ovipositor. The slit is at an angle to the surface and the posterior 

 end of the egg is at the bottom, while the anterior (head) end is at the 

 opening quite visible from the surface and often projecting slightly 

 above it. 



By far the greater number of eggs are laid in the outer surface of 

 the sheath round the stigma or young pod formfed, in leguminous 



16—2 



