That's a population worth an application of insecticidal soap, in my opinion. The slightly caustic soap will dissolve the 'spit ' and those plant sucking larvae will be more vulnerable. Spray on a cloudy or overcast day, if possible.

catman, I've seen one or two praying mantis around our yard since we've lived here but we have many, many hummingbirds and enjoy watching them. Needless to say, I'd freak if I saw once being eaten by a mantis. I do like the mantis too because they are so interesting to observe.

It's one of the "false Widow" spiders, Steatoda grossa. These are, as Jean001a pointed out, in the Theridiidae family, which includes true Widows( genus Latrodactus) and the American House Spiders. These, however, are not considered "medically significant" in terms of venom.

Looks like one of the many kinds of what are called 'grass spiders', perhaps an Angelenopsis species. They make the small sheets of webs you see on top of the lawn and shrubs after a heavy dew.