August, '17] ESSIG: TOMATO AND LAUREL PSYLLIDS 433 



5. Unguis of segment VI about twice as long as the base beulahensis (Ckll.) 



Unguis of segment VI one and one-haK times as long as base media Baker 



6. Cornicles nearly twice as long as the hind tarsi 7 



Cornicles much more than twice as long as the hind tarsi 8 



7. Unguis of segment VI of antennae about equal in length to the cornicles and 



about twice as long as base bicolor (Oest.) 



Unguis of segment VI of antennae considerably shorter than the cornicles and 

 not twice as long as base •popiilifolice (Fitch) 



8. Cornicles swollen in the middle, bright orange in color salicis (Linn.) 



N. B. Melanoxantherium antennatum Patch is known only from the oviparous 



female. 



Literature Referred to in Text 



1851. Fitch, Asa. Cat. with references and descriptions of the insects collected and 

 arranged for the State Cabinet of Natural History. In 4th Ann. Rept. State 

 Cab. Nat. Hist., pp. 43-69. 



1855. Fitch, Asa. Report on the Noxious and Other Insects of the State of New 

 York. In Trans. N. Y. State Agr. Soc, vol. 14, 1854, pp. 705-880. Also 

 printed Albany, N. Y. 176 p. 



1856. Fitch, Asa. Third Report on the Noxious and Other Insects of the State of 

 New York. In Trans. N. Y. State Agr. Soc, vol. 16, 1856, pp. 315-490. 



1879. MoNELL, J. T. Notes on AphididiB with Descriptions of New Species. 



In Bui. of the U. S. Geo!, and Geograph. Survey of the Territories, vol. V, 



No. 1, pp. 18-32 

 1887. Oestlund, O. W. Synopsis of the Aphididse of Minn. Bui. No. 4, Geol. and 



Nat. Hist. Survey of INIinn., pp. 1-100. 



1909. Davis, J. J. Studies on Aphididse II. In Ann. Ent. Soc. Am., vol. II, pp. 

 30-45. 



1910. Davis, J. J. Two Curious Species of Aphididte from Illinois. In Ent. 

 News, vol. XXI, pp. 195-200. 



1910. Gillette, C. P. Plant-louse Notes — Familj- Aphididse. In Jour. Econ. 



Ent. vol. Ill, p. 367. 

 1910. Williams, T. A. Aphididse of Nebraska. In University Studies, vol. X, 



No. 2, pp. 1-91. 



1913. Goot, p. VAX der. Zur Systematik der Aphiden. In Tijdschrift voor 

 Entomologie, vol. 56, pp. 69-154. 



1914. Davidson, W. M. Plant-louse Notes from California. In Jour. Econ. Ent., 

 vol. VII, pp. 127-136. 



THE TOMATO AND LAUREL PSYLLIDS 



By E. O. EssiG, Universiiy of California, Berkeley, Cal. 



Psyllids are also known as jumping plant-lice because of their great 

 similarity in appearance and habits to these insects and their ability 

 to jump freely. The family Psyllida to which psyllids belong is 

 usually placed next to the isnaily Aphididce (plant-Uce), in the suborder 

 Homoptera and the order Hemiptera. In this order are to be found 

 many of the insects which are very injurious to crops grown in Cali- 

 fornia. 



