52 MR. P. R. AWATI ON THE MECHANISM 
come within the scope of this paper to deal with the pathological 
effects due to the insect-bites; but the way in which these holes 
ave drilled is described below. 
The structure and the shape of the stylets have been described 
above. The tips of the maxillary stylets are smooth and lancet- 
shaped, but those of the mandibles are deeply serrated (text- 
fig. 23). The tip of the proboscis is covered with stiff hairs and 
is blunt. How the stylets work inside the plant-tissue has been 
described above. The insect is found on the same place for hours 
at a stretch. It withdraws its stylets every few minutes from the 
plant-tissues and thrusts them in again. ‘This process is repeated 
many times. Since the mandibles can only be withdrawn by 
tearing the cells each time they are taken out with their. recurved 
hooks (text-fig. 25), and as this process is repeated many times, 
a big area 1s “ultimately macerated and a hole is formed there 
afterwards. 
Tt was held by many writers—Dr. Riley being one of them— 
that the Heteroptera made holes with the proboscis, the Homo- 
ptera with the stylets. This view is absolutely inaccurate, since 
it is found that the proboscis is incapable of drilling holes, its 
tip being too thick and blunt to pierce the epidermis. Sections 
of plants taken with the stylets iz situ show that the stylets 
enter the tissues, the proboscis itself remaining outside, as 
deseribed above. 
BIBLIOGRAPHY. 
(1) Braun (Max). 1910.—A Handbook of Practical Parasitology. 
(2) Biseen (M.). 1891.—Der Honigtau. Jena. Zeitschr., Bd. xxv. 
(3) Boenton (B.) et Pororr (N.). i903.—L’appareil salivaire des Hémiptéres. 
Arch. d’Anat. micr., t. x. fase. ii.; t. xi. fase. iv. 
(4) Buenron (E.) et Poporr (N.). 1911.—Les piéces buccales des Hémiptéres. 
Premiére partie. Arch. Zool. expér., sér. 5, tome vil. 
(5) Burmetster. 1835.—Handbuch der Entomologie, II. Rhynchota. 
(6) Comstock and Koocnt., 1902.—The Skeleton of the Head of Insects. The 
American Naturalist, vol. xxxvi. 
(7) Craee (Capt.). 1913.—Studies on the Mouth-parts and the Sucking Apparatus 
of the Blood-sucking Diptera. Scientific Memoirs by Officers of the 
Medical and Sanitary Department of the Government of India, 
Nos. 58, 59. 
(8) DANEDSON | (J.). 1913.—Biological Study of Schizoneura lanigera. Q.J.M.S, 
vo vill. 
(9) Dimmockx. 1881.—The Anatomy of the Mouth-parts and the Sucking 
Apparatus of some Diptera. 
EO) ae oa: 1866.—Zur Anatomie der Hemipteren. Stettin. Entom. Zeit., 
ahrg. 27. 
(11) Dreyrvus (L.). 1894.—Phylloxeriden. Zool. Anz. Bd. xvii. pp. 221-235. 
(12) Dvrour (L). 1821—Anatomie de la Rantre linéaire et la Népe cendrée. 
Ann. Génér. des Sciences phys. nat. Bruxelles, t. vil. 
(18) Gets (O.). 1883.—Mundtheile der Rhy nchoten. Archiv f, Naturg. 
Bd. xlix. pp. 315-373. 
(14) ae 1853.—Ueber die Mundtheile der saugenden Insekten. 
eipzig. : 
(15) GrapeEr. 1877.—Die Insekten, Theil I. (Muiinchen.) 
(16) Grovs (A. J.). 1909.—Anatomy of Stphonophora rosarum. Parasitology, . 
vol. i1., 1909. 
(17) Handbuch der Vergleichenden Physiologie, 1911. Bd. ii. Halfte i.. 2 
(18) Heymons (R.). 1896.—Die Mundtheile der Rhynehota (Homoptera— 
Heteroptera). Entom. Nachrichten, Jahre. xxii. No. 11. 
a 
