October, '16] ESSIG; chrysanthemum GALL-MIDGE 467 



a description is to appear elsewhere. The adults are black with yellow- 

 markings on the legs. The females vary from 1 mm. to 1.2 mm. in 

 length and the males are somewhat smaller. Some of the details in 

 figure 33 will aid in distinguishing it. The larvse live within the galls 

 alongside the maggots of the gall-fly which they gradually consume. 

 They remain within the galls until mature when they emerge through 

 small circular holes. This species is the most abundant during the 

 summer months and all of the adults were reared during August, 

 September and October. In not a few cases as high as 80 per cent 

 to 90 per cent of the maggots were destroyed. 



Tetrastichus sp. (Fig. 34). The generic determination of this insect 

 was made by Mr. Harry S. Smith, Superintendent of the State Insec- 

 tary, Sacramento, California. It ife also a small black parasite some- 

 what larger than the former and easily distinguished from it by the 

 four-jointed tarsi and other characters shown in the accompanying 

 drawings. 



Bibliography^ 



Ferris, D. Ann. Soc. Ent. Fr., 10, 177, 1870 



Vox Bergenstamm, J. E. & Low, F. Syn. Cecidomyidarum, no. 516, p. 90, 1876 



(no name). 

 Low, Franz. Verh. Zool.-Bot. Ges. Wien, 35, p. 488, 1885, Cecidomyia. 

 RuBSAAMEN, E. H. Bed. Ent. Zeitsschr., 37, p. 375, 1892, Rhopalotnyia. 

 KiEFFER, J. J., Bui. Soc. Ent. France, p. 261, 1897, Rhopalomyia. 

 KiEFFER, J. J. Bul. Soc. Hist. Nat. IMetz (2), t. 8, p. 21, 1898, Rhopalomyia. 

 Baldrati, J. Xuovo Giorn. bot. Ital Firenze, 32, no. 86, p. 40, pi. 3, 1900. 

 Kertesz, C. Catalogus Dipterorum, 2, p. 69, 1902. Rhopalomyia. 

 Lemee, E. Alengon Bul. Soc. hortic, separate, no. 131, p. 38, 1902. 

 Houard, C. Les Zoocccidics des Plantes d'Europ., etc., 2, p. 988; 3, p. 1483, 1909, 



Rhopalomyia. 

 KusTER, Ernst. Die Gallen der Pflanzen, pp 77,274, 1911, Rhopalomyia. 

 KiEFFER, J. J. Gen. Ins. fascicle, 152, p. 46, 1913, Misospatha. 

 Felt, E. P. American Florist, 44, p. 612, Apr. 10, 1915. 

 Felt, E. P. Jr. Ec. Ent., 8, p. 267, Apr. 1915, Rhopalomyia. 

 Felt, E. P. Tree Talk, 2, no. 4, p. 27, May 1915. 

 Felt, E. P. 31st Kept. State Ent. N. Y., pp. 12, 51-55, 90, pi 13, June 1, 1916. 



1 Since preparing this article some months ago the writer has received a cop}^ of the 

 31st Report of the State Entomologist of the State of New York, June 1, 1916, from 

 Dr. Felt and finds that the subject matter is much more thoroughly handled and that 

 this paper \\'ould not be worth printing were it not for the local interest to California. 



The above bibliography is taken entirely from Dr. Felt's paper with a rearrange- 

 ment and a few minor changes. i^ 



Other locahties given in Dr. Felt's paper are Oregon, and Ottawa, Canada, and the 

 additional European host plants: Chrysanthemum corymbosum, C. atratum, C.japon- 

 icum and C. myconis. The varieties of C. japonicum are very generally infested in 

 this district. 



The technical description of the various stages is very complete in the above men- 

 tioned paper. 



