34 REPORTS OF OBSERVATIONS AND EXPERIMENTS. 



A fungous disease appears to have destroyed large numbers during 

 the early summer. It was only at picking time that the lice became 

 numerous, and in consequence the coming season may again show an 

 increase. As already mentioned, the importance of an early warfare 

 against the hop louse can not be overestimated. Spraying and hand- 

 picking should be practiced upon all the plum and prune trees during 

 the autumn and early spring. 



Since the season has been so backward it is not possible for me to 

 give a list of the most efficient enemies of the hop louse, viz, the 

 Syrphid flies, and but few of these were observed during my work. 

 Coccinellidae, however, could be seen by the thousands during early 

 spring. I give a list of those met with in the yards, with notes thereon. 



Notes on Ladybirds found in Hop Yards. — The largest number were of 

 the genus Hippodamia, and it is a difficult matter even for an expert to 

 define the species when seeing large numbers together. Hippodamia 

 convergens Guer. and H. ambigua Lee. were the most numerous in the 

 hop yards during the early spring and were preying upon various 

 Aphidids infesting weeds. After devouring all these, they, as well as 

 all other species, left in all directions and could be found almost any- 

 where where plant-lice existed. As observed, these insects will also 

 prey upon Lecanium in its young stages after the most of the Aphidids 

 have disappeared. H. 13-punctata has been but rarely met with. H. 

 spuria Lee. and H. parenthesis Say were more numerous and always 

 upon plant-lice. CoccincIIa annectans Crotch is a rare insect that feeds 

 upon Aphidids as well as upon the young of Lecanium. Cocci nella 

 trifasciata Linn, is an abundant ladybird that is found feeding any- 

 where upon plant-lice, and as these become rare with the advance 

 of the season, it readily feeds upon bark-lice. C. transversoguttata 

 Fab. is one of the largest of this group and was also found in numbers 

 in the hop yards as long as the plant-lice upon which it preys existed. 

 The first eggs of any found amongst hop vines belonged to this species. 

 This was before the yards were plowed, which will destroy nearly, if 

 not all, the early stages of these valuable insects. Cycloneda sanguined 

 Linn, is a very common ladybird and one of the most active in hunting 

 up the solitary Aphidids. Many colonies of the hop louse under 

 observation on pluin and prune trees were entirely cleaned out by this 

 beetle and often in a single day. In order to get at the proper results 

 of the experiments it often becomes necessary to cover the lice treated 

 with netting on account of this insect. Adalia bipnnctata Linn, is only 

 occasionally found. I have bred the same from larvae feeding upon an 

 Aphidid infesting Crataegus at Sisson, Cal. It has also been found near 

 Alameda, upon orange trees infested with Lecanium. 



A. humeralis Say was found feeding upon plant-lice in Oregon and in 

 California. I found it more often upon plants infested with black 

 scale. A very common and variable ladybird is Harmonia picta 

 Rand,, which is met with occasionally feeding upon plant-lice. The 



