50 BRITISH GALLS 



Miss Ormerod observes that "the maggots bear being frozen 

 hard without the slightest apparent injury, for on being 

 thawed they will at once go down into soft earth and begin 

 to build up their earth- cases." 



C. sulcicoUis Gyll. must be carefully distinguished from 

 C. sulcicolUs Paykull. The latter is not a British insect ; 

 there are Italian records of its larvae causing large fusiform 

 swellings on stems of Deniaria pinnata Linn. 



Plate VI., Fig. 4, shows the Common Whitlow Grass with 

 a spherical gall on the upper part of its root, caused by the 

 presence of the larva of Ceuthorrkynchus hirtulus. Fig. 5 

 gives a magnified view of the insect, and Fig. 6 the gall 

 twice actual size. This beetle is not common. The gall 

 sometimes occurs at the base of the stem, amongst the 

 rosette of leaves. 



Three species of Cmthowhynchus cause galls on the Hedge 

 Mustard. The catalogue should be consulted for particulars 

 of these and many others. 



Large galls are sometimes caused by the larvae of Saperda 

 populnea in Poplar and Willow stems in the southern 

 counties. This beetle belongs to the Longicorn family 

 (Cerambycidae), which comprises insects of oblong shape, 

 with long antentiae, and elytra often dull from the presence 

 of minute hairs, which are frequently arranged in patterns. 

 Its life-history is briefly as follows : In June, or early in 

 July, the female, upon finding a suitable young branch, cuts 

 a shield-like mark in the bark, and deposits a single egg at 

 the base of the shield (Plate VI., Fig. 7, a). This operation 

 is repeated three or four times along the same branch at 

 intervals of about 30 mm. It is said that the presence of 

 the egg starts the hypertrophy, but it is more probable that 

 no swelling begins to take place until the larva (Fig. 11) is 

 hatched. The larva eats its way into the pith, making 

 galleries above and below the entrance-hole, and remains 

 in the larval state until the second autumn, when it pupates 

 in the branch. In the following June or July the imago 

 emerges from a hole in the swelling, which is usually on 



