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380Compounds 38617, 38650, and 38694 were ineffective even at the 0.5% level. A phytotoxic response was noted at the 0.5% level in onty 2 of the materials, 20702-c and 36313. Although little can be said concerning structure-activity relationships among these compounds, the results suggest that the presence of a methoxy group ortho to the THP group considerably increases the activity of the THP ether of unsubstituted phenol (36235), Even greater improvement is obtained by the presence of a dioxymethylene group on the phenol molecule. Suprisingly, though the THP ether of 3,4-methylenedioxybenzyt alcohol (20702-c) is not derived from a phenol, it proved to be one of the most effective compounds in this series. It was noted that, though the THP ethers of 2-hydroxybenzaldehyde and of 2-hydroxy-5methoxybenzaldehyde are not effective at either concentration, the THP ether of 2-hydroxy-4-methoxybenzaldehyde is highly effective even at the 0.1% level. These data add to the numbers of materials which are promising as feeding deterrents for striped cucumber beetle 5. As the beetle is a significant problem on cucurbits due to both its feeding and transmission of disease, an effective antifeedant would be an attractive alternative to present control tactics. Experientia 39 (I983), Birkh~user Verlag, CH-4010 Basel/SwitzerlandSummary. The occurrence of 3-methyl-2-hexanone as a major component of the secretion and possible alarm substance from the metasternal scent glands in the triatomine bug Dipetalogaster maximus is reported.Dipetalogaster maximus (Uhler) is a very large 33-42 mm long blood sucking (triatomine) bug. It occurs naturally in Mexico at the extreme southern tip of semi-arid California Baja (Sur) z. Trypanosoma cruzi, which causes Chagas' disease in humans, is transmitted by triatomine bugs. Although D. maximus is not, because of its restricted distribution, important as a carrier of T. cruzi 2 the early larval stages are proving useful in xenodiagnosis, as a natural means of detecting T. cruzi in patients suspected of having Chagas' disease 3. In the efforts which continue to be made to secure improvements in the techniques used to detect and control the noxious triatomines searches have been made for behavior modifying chemicals which the insects themselves produce 4. Here we should like to report evidence indicating that 3-methyl-2-hexanone is a major component of the secretion and a possible alarm substance from the metasternat (= metathoracic) scent glands olD. maximus. Materials and methods. Larvae and adults of D. maximus were obtained from Cambridge, England I (the larvae were reared to adulthood in our laboratory, in Cardiff). The metasternal scent glands were isolated by dissection under 200 mM NaC1. They are present only in the adult insect. The electron impact gas chromatographic-mass spectrometric (GC-MS) analyses 1 were carried out using a 7070H VG mass spectrometer at 70 eV with the ion source temperature 190~separator 180~ and 200 ~tA ionizing current. Separations were achieved with a 2 m • 2 mm i.d...

The isolation and identification of (Z,E)-α-farnesene[(3Z, 6E)-3,7,11-trimethyldodeca-1,3,6,10-tetraene] (III) as the major component of the secretion from the metathoracic scent gland of the cotton seed bug,Oxycarenus hyalinipennis, is reported. The compound was identified by a combination of [1H] NMR, [(13)C] NMR, UV, and mass spectral data and by comparison with a synthetic sample, prepared by dehydration of (E)-nerolidol. (Z,E)-α-Farnesene (III) has been recorded previously in insects (ants and termites), but this is the first report of its occurrence in a member of the Heteroptera. (E)2-Octenyl acetate (XIII) and 2-octenal (XIV) were identified as minor components of the secretion. In addition, three minor monoterpenoid and two other sesquiterpenoid components were detected and tentatively identified.

Pheromone glands are present in the abdominal sternites of the pregenital region in the male adults in all British species of Acanthosomatidae. Secretory units are most numerous in the hawthorn bugAcanthosoma haemorrhoidale and maternal bugElasmucha grisea, next most numerous in the birch bugElasmostethus interstinctus, and least numerous in the juniper bugCyphostethus tristriatus. The largest dorsal abdominal scent glands were found inCyphostetheus. Ordinary dermal glands are also present. They are most numerous along the lateral margins of the abdomen. It is possible that Pendergrast's organ is the source of a female-produced pheromone. Secretory units were numerous in this organ inC. tristriatus female adults.