188 



HUTSON (J. C). The Sweet Potato Root Weevil. — Agric. Neivs, 

 Barbados, xvii, no. 412, 9th February 1918, pp. 42-43, 1 fig. 



The sweet potato root weevil {Cylas formicarius) is a pest that 

 cannot be eliminated from a district where it has become well estab- 

 lished, though much may be done to reduce the damage caused by 

 it. According to Mr. Wilmon Newell this pest is disseminated by the 

 movement of infested sweet potatoes, both tubers and plants, from 

 one district to another and not by flight, the adults, although possess- 

 ing well-developed wings, having rarely been observed to fly. The 

 favourite host-plants are the sweet potato {Ipomoea batatas) and the 

 morning glory {Ipomoea sp.), though the adults can feed on a great 

 variety of vegetation. This weevil is remarkably free from natural 

 enemies, no parasites or birds predaceous on it ha\'ing been recorded. 

 Of artificial control methods, quarantine measures are the most 

 important, those adopted by the Plant Board of Florida having 

 already been noticed [see this Review, Ser. A, vi, p. 40]. Fumigation 

 of the tubers destroys the insect in all its stages, using carbon bisul- 

 phide at the rate of 3 lb. to each 1,000 cubic feet of space. Damage 

 done by the weevil and also by the scarabee or Jacobs [Euscepes 

 batatae] can be greatly reduced by clean cultivation methods, such 

 as using only those plants that are known to have come from a 

 weevil-free locality ; collecting and burning all vines, damaged tubers, 

 pieces of root, etc., after harvesting the crop ; burning damaged 

 sweet potatoes, or boiling them if they are needed for feeding stock ; 

 preventing the spread of the insect by separating the sweet potato 

 patches as widely as possible and not planting the crop on the same 

 land for two successive seasons. 



Bruch (C). Metam6rfosis de Pachyschelus undularius, Burm. (Cole- 

 6ptero bupr6stido). [Metamorphosis of the Buprestid, Pac%sc^e?MS 

 undularius, Burm.] — Physis, Buenos Aires, iii, no. 13, 17th March 

 1917, 2 plates. [Received 7th March 1918.] 



The small Buprestid, Pachyschelus undularius, lives on Sapium 

 biglanduhsmn, which is common in the forests around Buenos 

 Aires and La Plata. Adults are found during the summer, in Decem- 

 ber and January, upon the leaves of the host-tree, while the white 

 froth on the leaves reveals the presence of the larvae, which devour 

 the parenchyma of the leaves. While mining between the two surfaces 

 of the leaf, the larva throws out an abundant latex on to the surface. 

 This habit has been noticed in the case of larvae of other Coleoptera, 

 and particularly very recently in the case of an allied Buprestid of 

 the same genus from Paraguay. Eggs are laid on the under-surface 

 of the leaf, the female making a number of incisions in the leaf to 

 facilitate the work of the newly-hatched larva. The egg hatches 

 after 5 to 6 days and the larva develops rapidly, reaching maturity in 

 about two months. During this period a great quantity of froth is 

 thrown out on to the surface of the leaf. Upon reaching maturity, 

 the larva constructs a sort of disc at the end of its mine in which 

 it transforms into a nymph. Under this disc it may remain from ten 

 days to two months in a quiescent state before pupating. The 



