171 



from 12 to 15 months. In Kent oviposition began in April and con- 

 tinued to July, the eggs being laid indiscriminatel}- amongst the earth 

 at the base of the plants. Thej^ hatch in about 21 days, and the 

 larvae burrow through the earth to the roots and enter the nodules, 

 on which they feed. The larval stage lasts about 7 weeks. Pupation 

 occurs in a cell excavated in the soil, and lasts from 16 to 19 days, 

 but the weevils remain in the soil 5 to 6 days longer. The first weevils 

 emerge from the soil about July, and begin at 'once feeding on peas 

 and beans. As the plants are full grown, very little damage is caused 

 at this time. When the crop is harvested, most of the weevils disperse, 

 but some are carried with the crops, and a few may be found in the 

 field in midwinter. These adults do not oviposit until the following 

 spring, a fact that has been conclusively proved by a study of the 

 reproductive organs, details of which are described. 



The natural enemies include birds, a mite {Tromhidium sp.) and the 

 Braconids, PeriliUis rutiliis, 'Nees.Pygostolus falcatus, Nees, and Liophron 

 inuricatus, Hal. var. nigra. The fungus, Botrytis bassiana, is always 

 fatal to the weevils, and experimentally it has also proved fatal to 

 pupae and larvae in all stages. Successful experiments have been 

 made in infecting the weevils with spores of this fungus, and this 

 work is to be continued on a larger scale. 



A key is given to the British species of the genus Sitones found on 

 leguminous crops, adapted, with some alterations, from Fowler. 



Ritchie (W.). The Structure, Bionomics and Economic Importance 

 oS Saperda carc/iayias. Linn., "The large Poplar Longhorn."— 



Ann. App. Biol, Cambridge, vii, no. 2-3, December 1920, pp 

 299-343, 4 plates, 25 figs. 



The observations here described were made chiefly in Aberdeen- 

 shire, where Saperda carcharias, L., attacks Popidus tremula. 

 In captivity this beetle feeds readily on many varieties of poplar, 

 and eggs were laid on black Italian poplar (P. monilifera). A descrip- 

 tion is given of the various stages as well as of the "characters of the 

 genus Saperda. The adults appear from July to mid-August. The 

 eggs are laid in the stems of healthy trees, a smooth portion of the 

 bark near the base of the tree being generally selected and the eggs 

 inserted into a sht. If the bast layer is thin, such as on stems between 

 five and twelve years old, the eggs are placed between the cambium 

 and sapwood, but in older trunks they are found between the tissues 

 of the bast. One egg only is inserted in each incision, but in badly 

 mfested trees the incisions may be verv close together. The first 

 wmter is passed in the egg-stage, which lasts about IQi months. The 

 larvae on emerging, about July, feed on the tissues immediately sur- 

 rounding them. They then cut into the sapwood in an horizontal 

 direction for about | to 1 inch and turn downwards, gnawing gradually 

 deeper until the centre of the stem is reached. On reaching the root 

 portion, the larva turns and tunnels up the centre, a hole being bored 

 on the way through the sapwood and bast for the emergence of the adult. 

 The tunnel is continued up the centre of the stem to'a height of about 

 2 ft. Excluding the hibernation period, the larval gallery takes about 

 ^ months to complete. Hibernation occurs from about October 

 to March. The larval period lasts about 23 months, and the total 

 hfe-C3^cle in Scotland is about 4 years. If many larvae are at work 

 in one stem their galleries may be very irregular, and they often develop 



