The Pea Thrips. 



201 



" pungled matter," which is the expressive term applied by- 

 Curtis to wheat plants similarly affected by another species 

 of Thrips, known as Thrips cerealiiim. 



Thus, there was the unusual spectacle of whole rows of pea- 

 plants of over average size, good colour, and apparent health, 

 without flowers and pods, and utterly useless. Upon exami- 

 nation by a casual observer, the insects would hardly be 

 discovered, as they are very minute, and if noticed they 

 might very naturally be regarded from their size as too 

 insignificant to cause such wholesale mischief. 



Life History. 



The Thrips found in these pea-plants is probably the same 

 species of Thrips as that observed and described by West- 

 wood as infesting and injuring pea-plants in precisely the 

 same manner as has been described above. Westwood 

 regarded this as an unnamed species, and styled it Thrips 

 pisivora, and from his figure and descriptions it seems 

 probable that it is identical with the specimens forwarded to 

 the Board of Agriculture. In size it is hardly the twelfth of 

 an inch in length when full grown, and in the larval state it 

 is not quite so long. The insect is greyish yellow in colour 

 without wings, and possesses seven-jointed hairy antennae, 

 four of the upper joints being yellowish and the lower ones 

 black. The eyes are red, and the mouth is furnished with 

 a short fleshy sucking apparatus ; there are three pairs of 

 legs, with feet shaped like bladders, which is characteristic 

 of some species of Thripidce ; and at the end of the body there 

 is a brown or reddish brown ovipositor. The winged 

 specimens of the Thrips found on the pea-plants were darker 

 in colour, and had two pairs of wings with long fringes, 

 folded down the whole length, and extending beyond the 

 body. Westwood, in his description of the pea thrips, 

 evidently holds that the females of this species are wingless, 

 as he says, " We met with no males, unless indeed a very few 

 other black fully winged specimens may be of that sex/' In 

 the case of some species of Thrips, as Thrips cerealium, for 

 instance, the males are winglesSc The female places eggs of 

 microscopic size close to the midribs of the leaves, from which 



