THE INSECT FAUNA OF THE GENUS CRATAEGUS 



1085 



FlG. 122. PINEAPPLE GALLS 



a leaf and it is commonly on the 



a long;, narrow slit on the oppo- 

 site side of the leaf. These galte 

 occur very commonly in groups 

 on the same leaf or on adjoining 

 leaves. A single yellow larva, 

 1 millimeter long, and slender, 

 is found in each gall in July or 

 August. 



Pineapple gall (maker unknown) 



Red or green spiny galls, 

 shaped and armored like a pine- 

 apple (figs. 122, 123, and 124), 

 M millimeters in diameter and 

 5 millimeters high, are found 

 on the upper side of Crataegus 

 punctata leaves in July and 

 August. The pineapple gall is 

 thick and is covered with fleshy 

 spines at the base, but becomes 

 slender, with long, slender 

 spines, toward the apex, which 

 is composed of two flat, leaflike, 

 vertical plates. The gall opens 

 between these two plates. Gen- 

 erally .but one gall is found on 

 midvein. 



Trypetidae 



pomonella Walsh, Rhagoletis (Apple maggot) 



The maggots of Rhagoletis pomonella have been reared and flies obtained 

 from the fruits of Crataegus punctata, C. albicans, C. pruinosa, C. brainerdi, 

 and C. macrosperma. The species probably lives also in the fruits of 

 other large-fruited .hawthorns. 

 No larvae have been found in 

 the small fruits of C. neofluvialis 

 and C. oxyacantha, although 

 these have been carefully 

 watched. The maggots leave 

 the fruit to enter the ground 

 in autumn, and the flies emerge 

 from the brown puparia in June 

 and July. FIG. 123. SIDE VIEW OF PINEAPPLE GALL 



